Method and apparatus for beam recovery in next generation wireless systems

ABSTRACT

A method of a user equipment (UE) for a beam failure recovery procedure in a wireless communication system is provided. The method comprises receiving, from a base station (BS), at least one beam failure detection reference signal (RS) and at least one new candidate beam RS over a downlink channel; identifying a set of RS resources including an index for the at least one beam failure detection RS; identifying a set of RS resources including an index for the at least one new candidate beam RS; identifying a dedicated control-resource set (CORESET) received from the BS for a beam failure recovery request; transmitting, to the BS, the beam failure recovery request associated with a quality measurement of the at least one beam failure detection RS over a physical random access channel (PRACH); and receiving, from the BS, a beam failure response in response to the beam failure recovery request based on the dedicated CORESET indicated to the UE.

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

The present application claims priority to:

-   -   U.S. Provisional Patent Application Ser. No. 62/484,653, filed        on Apr. 12, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/487,235, filed        on Apr. 19, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/504,902, filed        on May 11, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/513,083, filed        on May 31, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/522,349, filed        on Jun. 20, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/529,918, filed        on Jul. 7, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/533,823, filed        on Jul. 18, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/543,596, filed        on Aug. 10, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/561,003, filed        on Sep. 20, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/563,987, filed        on Sep. 27, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/572,890, filed        on Oct. 16, 2017;    -   U.S. Provisional Patent Application Ser. No. 62/587,210, filed        on Nov. 16, 2017; and    -   U.S. Provisional Patent Application Ser. No. 62/607,714, filed        on Dec. 19, 2017.        The content of the above-identified patent documents are        incorporated herein by reference.

TECHNICAL FIELD

The present application relates generally to beam management. Morespecifically, this disclosure relates to beam recovery scheme in anadvanced wireless communication system.

BACKGROUND

In a wireless communication network, a network access and a radioresource management (RRM) are enabled by physical layer synchronizationsignals and higher (MAC) layer procedures. In particular, a userequipment (UE) attempts to detect the presence of synchronizationsignals along with at least one cell identification (ID) for initialaccess. Once the UE is in the network and associated with a servingcell, the UE monitors several neighboring cells by attempting to detecttheir synchronization signals and/or measuring the associatedcell-specific reference signals (RSs). For next generation cellularsystems such as third generation partnership-new radio access orinterface (3GPP-NR), efficient and unified radio resource acquisition ortracking mechanism which works for various use cases such as enhancedmobile broadband (eMBB), ultra reliable low latency (URLLC), massivemachine type communication (mMTC), each corresponding to a differentcoverage requirement and frequency bands with different propagationlosses is desirable.

SUMMARY

Embodiments of the present disclosure provide beam recovery scheme in anadvanced wireless communication system.

In one embodiment, a UE for a beam failure recovery in a wirelesscommunication system is provided. The UE includes a transceiverconfigured to receive, from a base station (BS), at least one beamfailure detection reference signal (RS) and at least one new candidatebeam RS over a downlink channel. The UE further includes a processoroperably connected to the transceiver, the processor configured toidentify a set of RS resources including an index for the at least onebeam failure detection RS, identify a set of RS resources including anindex for the at least one new candidate beam RS; and identify adedicated control-resource set (CORESET) received from the BS for a beamfailure recovery request. The transceiver is further configured totransmit, to the BS, the beam failure recovery request associated with aquality measurement of the at least one beam failure detection RS over aphysical random access channel (PRACH) and receive, from the BS, a beamfailure response in response to the beam failure recovery request basedon the dedicated CORESET indicated to the UE.

In another embodiment, a BS for a beam failure recovery in a wirelesscommunication system is provided. The BS includes a processor configuredto identify a set of reference signal (RS) resources including an indexfor at least one beam failure detection RS and identify a set of RSresources including an index for at least one new candidate beam RS. TheBS further includes a transceiver operably connected to the processor,the transceiver configured to transmit, to a UE, the at least one beamfailure detection RS and the at least one new candidate beam RS over adownlink channel, receive, from the UE, a beam failure recovery requestassociated with a quality measurement of the at least one beam failuredetection RS over a PRACH, wherein the processor is further configuredto identify a dedicated CORESET for the beam failure recovery request,and transmit, to the UE, a beam failure response in response to the beamfailure recovery request based on the dedicated CORESET indicated to theUE.

In yet another embodiment, a method of a UE for a beam failure recoveryin a wireless communication system is provided. The method comprisesreceiving, from a BS, at least one beam failure detection referencesignal (RS) and at least one new candidate beam RS over a downlinkchannel, identifying a set of RS resources including an index for the atleast one beam failure detection RS, identifying a set of RS resourcesincluding an index for the at least one new candidate beam RS;identifying a dedicated CORESET received from the BS for a beam failurerecovery request, transmitting, to the BS, the beam failure recoveryrequest associated with a quality measurement of the at least one beamfailure detection RS over a PRACH, and receiving, from the BS, a beamfailure response in response to the beam failure recovery request basedon the dedicated CORESET indicated to the UE.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller may beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items may be used,and only one item in the list may be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure;

FIG. 2 illustrates an example eNB according to embodiments of thepresent disclosure;

FIG. 3 illustrates an example UE according to embodiments of the presentdisclosure;

FIG. 4A illustrates a high-level diagram of an orthogonal frequencydivision multiple access transmit path according to embodiments of thepresent disclosure;

FIG. 4B illustrates a high-level diagram of an orthogonal frequencydivision multiple access receive path according to embodiments of thepresent disclosure;

FIG. 5 illustrates a transmitter block diagram for a PDSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 6 illustrates a receiver block diagram for a PDSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 7 illustrates a transmitter block diagram for a PUSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 8 illustrates a receiver block diagram for a PUSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 9 illustrates an example multiplexing of two slices according toembodiments of the present disclosure;

FIG. 10 illustrates an example antenna blocks according to embodimentsof the present disclosure;

FIG. 11 illustrates an example UE mobility scenario according toembodiments of the present disclosure;

FIG. 12 illustrates an example beam recovery according to embodiments ofthe present disclosure;

FIG. 13A illustrates a flow chart of a procedure for sending beamrecovery request according to embodiments of the present disclosure;

FIG. 13B illustrates another flow chart of a procedure for sending beamrecovery request according to embodiments of the present disclosure;

FIG. 14 illustrates a flow chart of a procedure for sending beamrecovery request on a first UL channel and a second channel n exampleaccording to embodiments of the present disclosure;

FIG. 15 illustrates an example use case of a vehicle-centriccommunication network according to embodiments of the presentdisclosure;

FIG. 16 illustrates an example SL interface according to embodiments ofthe present disclosure;

FIG. 17 illustrates an example resource pool for PSCCH according toembodiments of the present disclosure;

FIG. 18 illustrates an example DMRS configuration according toembodiments of the present disclosure;

FIG. 19 illustrates another example DMRS configuration according toembodiments of the present disclosure;

FIG. 20 illustrates an example PRB configuration according toembodiments of the present disclosure;

FIG. 21A illustrates an example DMRS configuration and pre-coder setaccording to embodiments of the present disclosure;

FIG. 21B illustrates another example DMRS configuration and pre-coderset according to embodiments of the present disclosure; and

FIG. 21C illustrates yet another example DMRS configuration andpre-coder set according to embodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 through FIG. 21C, discussed below, and the various embodimentsused to describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

The following documents and standards descriptions are herebyincorporated by reference into the present disclosure as if fully setforth herein: 3GPP TS 36.211 v14.2.0, “E-UTRA, Physical channels andmodulation;” 3GPP TS 36.212 v14.2.0, “E-UTRA, Multiplexing and Channelcoding;” 3GPP TS 36.213 v14.2.0, “E-UTRA, Physical Layer Procedures;”3GPP TS 36.321 v14.2.0, “E-UTRA, Medium Access Control (MAC) protocolspecification;” and 3GPP TS 36.331 v14.2.1, “E-UTRA, Radio ResourceControl (RRC) protocol specification,” 3GPP TR 22.891 v1.2.0,“Feasibility Study on New Services and Markets Technology Enablers.”

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a “beyond 4G network” or a“post LTE system.”

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission coverage, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques and the like arediscussed in 5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul communication, moving network,cooperative communication, coordinated multi-points (CoMP) transmissionand reception, interference mitigation and cancellation and the like.

In the 5G system, hybrid frequency shift keying and quadrature amplitudemodulation (FQAM) and sliding window superposition coding (SWSC) as anadaptive modulation and coding (AMC) technique, and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA) as an advanced access technology have beendeveloped.

FIGS. 1-4B below describe various embodiments implemented in wirelesscommunications systems and with the use of orthogonal frequency divisionmultiplexing (OFDM) or orthogonal frequency division multiple access(OFDMA) communication techniques. The descriptions of FIGS. 1-3 are notmeant to imply physical or architectural limitations to the manner inwhich different embodiments may be implemented. Different embodiments ofthe present disclosure may be implemented in any suitably-arrangedcommunications system.

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure. The embodiment of the wireless network shownin FIG. 1 is for illustration only. Other embodiments of the wirelessnetwork 100 could be used without departing from the scope of thisdisclosure.

As shown in FIG. 1, the wireless network includes an eNB 101, an eNB102, and an eNB 103. The eNB 101 communicates with the eNB 102 and theeNB 103. The eNB 101 also communicates with at least one network 130,such as the Internet, a proprietary Internet Protocol (IP) network, orother data network.

The eNB 102 provides wireless broadband access to the network 130 for afirst plurality of UEs within a coverage area 120 of the eNB 102. Thefirst plurality of UEs includes a UE 111, which may be located in asmall business (SB); a UE 112, which may be located in an enterprise(E); a UE 113, which may be located in a WiFi hotspot (HS); a UE 114,which may be located in a first residence (R); a UE 115, which may belocated in a second residence (R); and a UE 116, which may be a mobiledevice (M), such as a cell phone, a wireless laptop, a wireless PDA, orthe like. The eNB 103 provides wireless broadband access to the network130 for a second plurality of UEs within a coverage area 125 of the eNB103. The second plurality of UEs includes the UE 115 and the UE 116. Insome embodiments, one or more of the eNBs 101-103 may communicate witheach other and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WiFi,or other wireless communication techniques.

Depending on the network type, the term “base station” or “BS” can referto any component (or collection of components) configured to providewireless access to a network, such as transmit point (TP),transmit-receive point (TRP), an enhanced base station (eNodeB or eNB),a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point(AP), or other wirelessly enabled devices. Base stations may providewireless access in accordance with one or more wireless communicationprotocols, e.g., 5G 3GPP new radio interface/access (NR), long termevolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA),Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience, the terms “BS”and “TRP” are used interchangeably in this patent document to refer tonetwork infrastructure components that provide wireless access to remoteterminals. Also, depending on the network type, the term “userequipment” or “UE” can refer to any component such as “mobile station,”“subscriber station,” “remote terminal,” “wireless terminal,” “receivepoint,” or “user device.” For the sake of convenience, the terms “userequipment” and “UE” are used in this patent document to refer to remotewireless equipment that wirelessly accesses a BS, whether the UE is amobile device (such as a mobile telephone or smartphone) or is normallyconsidered a stationary device (such as a desktop computer or vendingmachine).

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with eNBs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the eNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116include circuitry, programming, or a combination thereof, for efficientbeam recovery in an advanced wireless communication system. In certainembodiments, and one or more of the eNBs 101-103 includes circuitry,programming, or a combination thereof, for receiving efficient beamrecovery in an advanced wireless communication system.

Although FIG. 1 illustrates one example of a wireless network, variouschanges may be made to FIG. 1. For example, the wireless network couldinclude any number of eNBs and any number of UEs in any suitablearrangement. Also, the eNB 101 could communicate directly with anynumber of UEs and provide those UEs with wireless broadband access tothe network 130. Similarly, each eNB 102-103 could communicate directlywith the network 130 and provide UEs with direct wireless broadbandaccess to the network 130. Further, the eNBs 101, 102, and/or 103 couldprovide access to other or additional external networks, such asexternal telephone networks or other types of data networks.

FIG. 2 illustrates an example eNB 102 according to embodiments of thepresent disclosure. The embodiment of the eNB 102 illustrated in FIG. 2is for illustration only, and the eNBs 101 and 103 of FIG. 1 could havethe same or similar configuration. However, eNBs come in a wide varietyof configurations, and FIG. 2 does not limit the scope of thisdisclosure to any particular implementation of an eNB.

As shown in FIG. 2, the eNB 102 includes multiple antennas 205 a-205 n,multiple RF transceivers 210 a-210 n, transmit (TX) processing circuitry215, and receive (RX) processing circuitry 220. The eNB 102 alsoincludes a controller/processor 225, a memory 230, and a backhaul ornetwork interface 235.

The RF transceivers 210 a-210 n receive, from the antennas 205 a-205 n,incoming RF signals, such as signals transmitted by UEs in the network100. The RF transceivers 210 a-210 n down-convert the incoming RFsignals to generate IF or baseband signals. The IF or baseband signalsare sent to the RX processing circuitry 220, which generates processedbaseband signals by filtering, decoding, and/or digitizing the basebandor IF signals. The RX processing circuitry 220 transmits the processedbaseband signals to the controller/processor 225 for further processing.

The TX processing circuitry 215 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 225. The TX processing circuitry 215 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 210 a-210 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 215 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or otherprocessing devices that control the overall operation of the eNB 102.For example, the controller/processor 225 could control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 210 a-210 n, the RX processing circuitry 220, andthe TX processing circuitry 215 in accordance with well-knownprinciples. The controller/processor 225 could support additionalfunctions as well, such as more advanced wireless communicationfunctions. For instance, the controller/processor 225 could support beamforming or directional routing operations in which outgoing signals frommultiple antennas 205 a-205 n are weighted differently to effectivelysteer the outgoing signals in a desired direction. Any of a wide varietyof other functions could be supported in the eNB 102 by thecontroller/processor 225.

The controller/processor 225 is also capable of executing programs andother processes resident in the memory 230, such as an OS. Thecontroller/processor 225 can move data into or out of the memory 230 asrequired by an executing process.

The controller/processor 225 is also coupled to the backhaul or networkinterface 235. The backhaul or network interface 235 allows the eNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The interface 235 could support communications overany suitable wired or wireless connection(s). For example, when the eNB102 is implemented as part of a cellular communication system (such asone supporting 5G, LTE, or LTE-A), the interface 235 could allow the eNB102 to communicate with other eNBs over a wired or wireless backhaulconnection. When the eNB 102 is implemented as an access point, theinterface 235 could allow the eNB 102 to communicate over a wired orwireless local area network or over a wired or wireless connection to alarger network (such as the Internet). The interface 235 includes anysuitable structure supporting communications over a wired or wirelessconnection, such as an Ethernet or RF transceiver.

The memory 230 is coupled to the controller/processor 225. Part of thememory 230 could include a RAM, and another part of the memory 230 couldinclude a Flash memory or other ROM.

Although FIG. 2 illustrates one example of eNB 102, various changes maybe made to FIG. 2. For example, the eNB 102 could include any number ofeach component shown in FIG. 2. As a particular example, an access pointcould include a number of interfaces 235, and the controller/processor225 could support routing functions to route data between differentnetwork addresses. As another particular example, while shown asincluding a single instance of TX processing circuitry 215 and a singleinstance of RX processing circuitry 220, the eNB 102 could includemultiple instances of each (such as one per RF transceiver). Also,various components in FIG. 2 could be combined, further subdivided, oromitted and additional components could be added according to particularneeds.

FIG. 3 illustrates an example UE 116 according to embodiments of thepresent disclosure. The embodiment of the UE 116 illustrated in FIG. 3is for illustration only, and the UEs 111-115 of FIG. 1 could have thesame or similar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 3 does not limit the scope of this disclosureto any particular implementation of a UE.

As shown in FIG. 3, the UE 116 includes an antenna 305, a radiofrequency (RF) transceiver 310, TX processing circuitry 315, amicrophone 320, and receive (RX) processing circuitry 325. The UE 116also includes a speaker 330, a processor 340, an input/output (I/O)interface (IF) 345, a touchscreen 350, a display 355, and a memory 360.The memory 360 includes an operating system (OS) 361 and one or moreapplications 362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by an eNB of the network 100. The RF transceiver 310down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 325, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 325 transmits the processed basebandsignal to the speaker 330 (such as for voice data) or to the processor340 for further processing (such as for web browsing data).

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 340.The TX processing circuitry 315 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 310 receives the outgoing processed basebandor IF signal from the TX processing circuitry 315 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 305.

The processor 340 can include one or more processors or other processingdevices and execute the OS 361 stored in the memory 360 in order tocontrol the overall operation of the UE 116. For example, the processor340 could control the reception of forward channel signals and thetransmission of reverse channel signals by the RF transceiver 310, theRX processing circuitry 325, and the TX processing circuitry 315 inaccordance with well-known principles. In some embodiments, theprocessor 340 includes at least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as processes for CSI reportingon PUCCH. The processor 340 can move data into or out of the memory 360as required by an executing process. In some embodiments, the processor340 is configured to execute the applications 362 based on the OS 361 orin response to signals received from eNBs or an operator. The processor340 is also coupled to the I/O interface 345, which provides the UE 116with the ability to connect to other devices, such as laptop computersand handheld computers. The I/O interface 345 is the communication pathbetween these accessories and the processor 340.

The processor 340 is also coupled to the touchscreen 350 and the display355. The operator of the UE 116 can use the touchscreen 350 to enterdata into the UE 116. The display 355 may be a liquid crystal display,light emitting diode display, or other display capable of rendering textand/or at least limited graphics, such as from web sites.

The memory 360 is coupled to the processor 340. Part of the memory 360could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes maybe made to FIG. 3. For example, various components in FIG. 3 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 340 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 3 illustrates the UE 116 configured as amobile telephone or smartphone, UEs could be configured to operate asother types of mobile or stationary devices.

FIG. 4A is a high-level diagram of transmit path circuitry. For example,the transmit path circuitry may be used for an orthogonal frequencydivision multiple access (OFDMA) communication. FIG. 4B is a high-leveldiagram of receive path circuitry. For example, the receive pathcircuitry may be used for an orthogonal frequency division multipleaccess (OFDMA) communication. In FIGS. 4A and 4B, for downlinkcommunication, the transmit path circuitry may be implemented in a basestation (eNB) 102 or a relay station, and the receive path circuitry maybe implemented in a user equipment (e.g. user equipment 116 of FIG. 1).In other examples, for uplink communication, the receive path circuitry450 may be implemented in a base station (e.g. eNB 102 of FIG. 1) or arelay station, and the transmit path circuitry may be implemented in auser equipment (e.g. user equipment 116 of FIG. 1).

Transmit path circuitry comprises channel coding and modulation block405, serial-to-parallel (S-to-P) block 410, Size N Inverse Fast FourierTransform (IFFT) block 415, parallel-to-serial (P-to-S) block 420, addcyclic prefix block 425, and up-converter (UC) 430. Receive pathcircuitry 450 comprises down-converter (DC) 455, remove cyclic prefixblock 460, serial-to-parallel (S-to-P) block 465, Size N Fast FourierTransform (FFT) block 470, parallel-to-serial (P-to-S) block 475, andchannel decoding and demodulation block 480.

At least some of the components in FIGS. 4A 400 and 4B 450 may beimplemented in software, while other components may be implemented byconfigurable hardware or a mixture of software and configurablehardware. In particular, it is noted that the FFT blocks and the IFFTblocks described in this disclosure document may be implemented asconfigurable software algorithms, where the value of Size N may bemodified according to the implementation.

Furthermore, although this disclosure is directed to an embodiment thatimplements the Fast Fourier Transform and the Inverse Fast FourierTransform, this is by way of illustration only and may not be construedto limit the scope of the disclosure. It may be appreciated that in analternate embodiment of the present disclosure, the Fast FourierTransform functions and the Inverse Fast Fourier Transform functions mayeasily be replaced by discrete Fourier transform (DFT) functions andinverse discrete Fourier transform (IDFT) functions, respectively. Itmay be appreciated that for DFT and IDFT functions, the value of the Nvariable may be any integer number (i.e., 1, 4, 3, 4, etc.), while forFFT and IFFT functions, the value of the N variable may be any integernumber that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).

In transmit path circuitry 400, channel coding and modulation block 405receives a set of information bits, applies coding (e.g., LDPC coding)and modulates (e.g., quadrature phase shift keying (QPSK) or quadratureamplitude modulation (QAM)) the input bits to produce a sequence offrequency-domain modulation symbols. Serial-to-parallel block 410converts (i.e., de-multiplexes) the serial modulated symbols to paralleldata to produce N parallel symbol streams where N is the IFFT/FFT sizeused in BS 102 and UE 116. Size N IFFT block 415 then performs an IFFToperation on the N parallel symbol streams to produce time-domain outputsignals. Parallel-to-serial block 420 converts (i.e., multiplexes) theparallel time-domain output symbols from Size N IFFT block 415 toproduce a serial time-domain signal. Add cyclic prefix block 425 theninserts a cyclic prefix to the time-domain signal. Finally, up-converter430 modulates (i.e., up-converts) the output of add cyclic prefix block425 to RF frequency for transmission via a wireless channel. The signalmay also be filtered at baseband before conversion to RF frequency.

The transmitted RF signal arrives at UE 116 after passing through thewireless channel, and reverse operations to those at eNB 102 areperformed. Down-converter 455 down-converts the received signal tobaseband frequency, and remove cyclic prefix block 460 removes thecyclic prefix to produce the serial time-domain baseband signal.Serial-to-parallel block 465 converts the time-domain baseband signal toparallel time-domain signals. Size N FFT block 470 then performs an FFTalgorithm to produce N parallel frequency-domain signals.Parallel-to-serial block 475 converts the parallel frequency-domainsignals to a sequence of modulated data symbols. Channel decoding anddemodulation block 480 demodulates and then decodes the modulatedsymbols to recover the original input data stream.

Each of eNBs 101-103 may implement a transmit path that is analogous totransmitting in the downlink to user equipment 111-116 and may implementa receive path that is analogous to receiving in the uplink from userequipment 111-116. Similarly, each one of user equipment 111-116 mayimplement a transmit path corresponding to the architecture fortransmitting in the uplink to eNBs 101-103 and may implement a receivepath corresponding to the architecture for receiving in the downlinkfrom eNBs 101-103.

5G communication system use cases have been identified and described.Those use cases can be roughly categorized into three different groups.In one example, enhanced mobile broadband (eMBB) is determined to dowith high bits/sec requirement, with less stringent latency andreliability requirements. In another example, ultra reliable and lowlatency (URLL) is determined with less stringent bits/sec requirement.In yet another example, massive machine type communication (mMTC) isdetermined that a number of devices can be as many as 100,000 to 1million per km2, but the reliability/throughput/latency requirementcould be less stringent. This scenario may also involve power efficiencyrequirement as well, in that the battery consumption should be minimizedas possible.

A communication system includes a Downlink (DL) that conveys signalsfrom transmission points such as Base Stations (BSs) or NodeBs to UserEquipments (UEs) and an Uplink (UL) that conveys signals from UEs toreception points such as NodeBs. A UE, also commonly referred to as aterminal or a mobile station, may be fixed or mobile and may be acellular phone, a personal computer device, or an automated device. AneNodeB, which is generally a fixed station, may also be referred to asan access point or other equivalent terminology. For LTE systems, aNodeB is often referred as an eNodeB.

In a communication system, such as LTE system, DL signals can includedata signals conveying information content, control signals conveying DLcontrol information (DCI), and reference signals (RS) that are alsoknown as pilot signals. An eNodeB transmits data information through aphysical DL shared channel (PDSCH). An eNodeB transmits DCI through aphysical DL control channel (PDCCH) or an Enhanced PDCCH (EPDCCH).

An eNodeB transmits acknowledgement information in response to datatransport block (TB) transmission from a UE in a physical hybrid ARQindicator channel (PHICH). An eNodeB transmits one or more of multipletypes of RS including a UE-common RS (CRS), a channel state informationRS (CSI-RS), or a demodulation RS (DMRS). A CRS is transmitted over a DLsystem bandwidth (BW) and can be used by UEs to obtain a channelestimate to demodulate data or control information or to performmeasurements. To reduce CRS overhead, an eNodeB may transmit a CSI-RSwith a smaller density in the time and/or frequency domain than a CRS.DMRS can be transmitted only in the BW of a respective PDSCH or EPDCCHand a UE can use the DMRS to demodulate data or control information in aPDSCH or an EPDCCH, respectively. A transmission time interval for DLchannels is referred to as a subframe and can have, for example,duration of 1 millisecond.

DL signals also include transmission of a logical channel that carriessystem control information. A BCCH is mapped to either a transportchannel referred to as a broadcast channel (BCH) when the BCCH conveys amaster information block (MIB) or to a DL shared channel (DL-SCH) whenthe BCCH conveys a system information block (SIB). Most systeminformation is included in different SIBs that are transmitted usingDL-SCH. A presence of system information on a DL-SCH in a subframe canbe indicated by a transmission of a corresponding PDCCH conveying acodeword with a cyclic redundancy check (CRC) scrambled with specialsystem information RNTI (SI-RNTI). Alternatively, scheduling informationfor a SIB transmission can be provided in an earlier SIB and schedulinginformation for the first SIB (SIB-1) can be provided by the MIB.

DL resource allocation is performed in a unit of subframe and a group ofphysical resource blocks (PRBs). A transmission BW includes frequencyresource units referred to as resource blocks (RBs). Each RB includesN_(sc) ^(RB) sub-carriers, or resource elements (REs), such as 12 REs. Aunit of one RB over one subframe is referred to as a PRB. A UE can beallocated M_(PDSC) RBs for a total of M_(sc) ^(PDSCH)=M_(PDSCH)·N_(sc)^(RB) REs for the PDSCH transmission BW.

UL signals can include data signals conveying data information, controlsignals conveying UL control information (UCI), and UL RS. UL RSincludes DMRS and Sounding RS (SRS). A UE transmits DMRS only in a BW ofa respective PUSCH or PUCCH. An eNodeB can use a DMRS to demodulate datasignals or UCI signals. A UE transmits SRS to provide an eNodeB with anUL CSI. A UE transmits data information or UCI through a respectivephysical UL shared channel (PUSCH) or a Physical UL control channel(PUCCH). If a UE needs to transmit data information and UCI in a same ULsubframe, the UE may multiplex both in a PUSCH. UCI includes HybridAutomatic Repeat request acknowledgement (HARQ-ACK) information,indicating correct (ACK) or incorrect (NACK) detection for a data TB ina PDSCH or absence of a PDCCH detection (DTX), scheduling request (SR)indicating whether a UE has data in the UE's buffer, rank indicator(RI), and channel state information (CSI) enabling an eNodeB to performlink adaptation for PDSCH transmissions to a UE. HARQ-ACK information isalso transmitted by a UE in response to a detection of a PDCCH/EPDCCHindicating a release of semi-persistently scheduled PDSCH.

An UL subframe includes two slots. Each slot includes N_(sym) ^(UL)symbols for transmitting data information, UCI, DMRS, or SRS. Afrequency resource unit of an UL system BW is a RB. A UE is allocatedN_(RB) RBs for a total of N_(RB)·N_(sc) ^(RB) REs for a transmission BW.For a PUCCH, N_(RB)=1. A last subframe symbol can be used to multiplexSRS transmissions from one or more UEs. A number of subframe symbolsthat are available for data/UCI/DMRS transmission isN_(symb)=2·(N_(symb) ^(UL)−1)−N_(SRS) where N_(SRS)=1 if a last subframesymbol is used to transmit SRS and N_(SRS) otherwise.

FIG. 5 illustrates a transmitter block diagram 500 for a PDSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the transmitter block diagram 500 illustrated in FIG. 5 isfor illustration only. FIG. 5 does not limit the scope of thisdisclosure to any particular implementation of the transmitter blockdiagram 500.

As shown in FIG. 5, information bits 510 are encoded by encoder 520,such as a turbo encoder, and modulated by modulator 530, for exampleusing quadrature phase shift keying (QPSK) modulation. A serial toparallel (S/P) converter 540 generates M modulation symbols that aresubsequently provided to a mapper 550 to be mapped to REs selected by atransmission BW selection unit 555 for an assigned PDSCH transmissionBW, unit 560 applies an Inverse fast Fourier transform (IFFT), theoutput is then serialized by a parallel to serial (P/S) converter 570 tocreate a time domain signal, filtering is applied by filter 580, and asignal transmitted 590. Additional functionalities, such as datascrambling, cyclic prefix insertion, time windowing, interleaving, andothers are well known in the art and are not shown for brevity.

FIG. 6 illustrates a receiver block diagram 600 for a PDSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the diagram 600 illustrated in FIG. 6 is for illustrationonly. FIG. 6 does not limit the scope of this disclosure to anyparticular implementation of the diagram 600.

As shown in FIG. 6, a received signal 610 is filtered by filter 620, REs630 for an assigned reception BW are selected by BW selector 635, unit640 applies a fast Fourier transform (FFT), and an output is serializedby a parallel-to-serial converter 650. Subsequently, a demodulator 660coherently demodulates data symbols by applying a channel estimateobtained from a DMRS or a CRS (not shown), and a decoder 670, such as aturbo decoder, decodes the demodulated data to provide an estimate ofthe information data bits 680. Additional functionalities such astime-windowing, cyclic prefix removal, de-scrambling, channelestimation, and de-interleaving are not shown for brevity.

FIG. 7 illustrates a transmitter block diagram 700 for a PUSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the block diagram 700 illustrated in FIG. 7 is forillustration only. FIG. 7 does not limit the scope of this disclosure toany particular implementation of the block diagram 700.

As shown in FIG. 7, information data bits 710 are encoded by encoder720, such as a turbo encoder, and modulated by modulator 730. A discreteFourier transform (DFT) unit 740 applies a DFT on the modulated databits, REs 750 corresponding to an assigned PUSCH transmission BW areselected by transmission BW selection unit 755, unit 760 applies an IFFTand, after a cyclic prefix insertion (not shown), filtering is appliedby filter 770 and a signal transmitted 780.

FIG. 8 illustrates a receiver block diagram 800 for a PUSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the block diagram 800 illustrated in FIG. 8 is forillustration only. FIG. 8 does not limit the scope of this disclosure toany particular implementation of the block diagram 800.

As shown in FIG. 8, a received signal 810 is filtered by filter 820.Subsequently, after a cyclic prefix is removed (not shown), unit 830applies a FFT, REs 840 corresponding to an assigned PUSCH reception BWare selected by a reception BW selector 845, unit 850 applies an inverseDFT (IDFT), a demodulator 860 coherently demodulates data symbols byapplying a channel estimate obtained from a DMRS (not shown), a decoder870, such as a turbo decoder, decodes the demodulated data to provide anestimate of the information data bits 880.

In next generation cellular systems, various use cases are envisionedbeyond the capabilities of LTE system. Termed 5G or the fifth generationcellular system, a system capable of operating at sub-6 GHz and above-6GHz (for example, in mmWave regime) becomes one of the requirements. In3GPP TR 22.891, 74 5G use cases has been identified and described; thoseuse cases can be roughly categorized into three different groups. Afirst group is termed ‘enhanced mobile broadband’ (eMBB), targeted tohigh data rate services with less stringent latency and reliabilityrequirements. A second group is termed “ultra-reliable and low latency(URLL)” targeted for applications with less stringent data raterequirements, but less tolerant to latency. A third group is termed“massive MTC (mMTC)” targeted for large number of low-power deviceconnections such as 1 million per km² with less stringent thereliability, data rate, and latency requirements.

In order for the 5G network to support such diverse services withdifferent quality of services (QoS), one method has been identified inLTE specification, called network slicing. To utilize PHY resourcesefficiently and multiplex various slices (with different resourceallocation schemes, numerologies, and scheduling strategies) in DL-SCH,a flexible and self-contained frame or subframe design is utilized.

FIG. 9 illustrates an example multiplexing of two slices 900 accordingto embodiments of the present disclosure. The embodiment of themultiplexing of two slices 900 illustrated in FIG. 9 is for illustrationonly. FIG. 9 does not limit the scope of this disclosure to anyparticular implementation of the multiplexing of two slices 900.

Two exemplary instances of multiplexing two slices within a commonsubframe or frame are depicted in FIG. 9. In these exemplaryembodiments, a slice can be composed of one or two transmissioninstances where one transmission instance includes a control (CTRL)component (e.g., 920 a, 960 a, 960 b, 920 b, or 960 c) and a datacomponent (e.g., 930 a, 970 a, 970 b, 930 b, or 970 c). In embodiment910, the two slices are multiplexed in frequency domain whereas inembodiment 950, the two slices are multiplexed in time domain. These twoslices can be transmitted with different sets of numerology.

LTE specification supports up to 32 CSI-RS antenna ports which enable aneNB to be equipped with a large number of antenna elements (such as 64or 128). In this case, a plurality of antenna elements is mapped ontoone CSI-RS port. For next generation cellular systems such as 5G, themaximum number of CSI-RS ports can either remain the same or increase.

FIG. 10 illustrates an example antenna blocks 1000 according toembodiments of the present disclosure. The embodiment of the antennablocks 1000 illustrated in FIG. 10 is for illustration only. FIG. 10does not limit the scope of this disclosure to any particularimplementation of the antenna blocks 1000.

For mmWave bands, although the number of antenna elements can be largerfor a given form factor, the number of CSI-RS ports—which can correspondto the number of digitally precoded ports—tends to be limited due tohardware constraints (such as the feasibility to install a large numberof ADCs/DACs at mmWave frequencies) as illustrated in FIG. 10. In thiscase, one CSI-RS port is mapped onto a large number of antenna elementswhich can be controlled by a bank of analog phase shifters. One CSI-RSport can then correspond to one sub-array which produces a narrow analogbeam through analog beamforming. This analog beam can be configured tosweep across a wider range of angles by varying the phase shifter bankacross symbols or subframes. The number of sub-arrays (equal to thenumber of RF chains) is the same as the number of CSI-RS portsN_(CSI-PORT). A digital beamforming unit performs a linear combinationacross N_(CSI-PORT) analog beams to further increase precoding gain.While analog beams are wideband (hence not frequency-selective), digitalprecoding can be varied across frequency sub-bands or resource blocks.

In a 3GPP LTE communication system, network access and radio resourcemanagement (RRM) are enabled by physical layer synchronization signalsand higher (MAC) layer procedures. In particular, a UE attempts todetect the presence of synchronization signals along with at least onecell ID for initial access. Once the UE is in the network and associatedwith a serving cell, the UE monitors several neighboring cells byattempting to detect their synchronization signals and/or measuring theassociated cell-specific RSs (for instance, by measuring their RSRPs).For next generation cellular systems such as 3GPP NR (new radio accessor interface), efficient and unified radio resource acquisition ortracking mechanism which works for various use cases (such as eMBB,URLLC, mMTC, each corresponding to a different coverage requirement) andfrequency bands (with different propagation losses) is desirable. Mostlikely designed with a different network and radio resource paradigm,seamless and low-latency RRM is also desirable. Such goals pose at leastthe following problems in designing an access, radio resource, andmobility management framework.

First, since NR is likely to support even more diversified networktopology, the notion of cell can be redefined or replaced with anotherradio resource entity. As an example, for synchronous networks, one cellcan be associated with a plurality of TRPs (transmit-receive points)similar to a COMP (coordinated multipoint transmission) scenario in LTEspecification. In this case, seamless mobility is a desirable feature.

Second, when large antenna arrays and beamforming are utilized, definingradio resource in terms of beams (although possibly termed differently)can be a natural approach. Given that numerous beamforming architecturescan be utilized, an access, radio resource, and mobility managementframework which accommodates various beamforming architectures (or,instead, agnostic to beamforming architecture) is desirable.

FIG. 11 illustrates an example UE mobility scenario 1100 according toembodiments of the present disclosure. The embodiment of the UE mobilityscenario 1100 illustrated in FIG. 11 is for illustration only. FIG. 11does not limit the scope of this disclosure to any particularimplementation of the UE mobility scenario 1100.

For instance, the framework may be applicable for or agnostic to whetherone beam is formed for one CSI-RS port (for instance, where a pluralityof analog ports are connected to one digital port, and a plurality ofwidely separated digital ports are utilized) or one beam is formed by aplurality of CSI-RS ports. In addition, the framework may be applicablewhether beam sweeping (as illustrated in FIG. 11) is used or not.

Third, different frequency bands and use cases impose different coveragelimitations. For example, mmWave bands impose large propagation losses.Therefore, some form of coverage enhancement scheme is needed. Severalcandidates include beam sweeping (as shown in FIG. 10), repetition,diversity, and/or multi-TRP transmission. For mMTC where transmissionbandwidth is small, time-domain repetition is needed to ensuresufficient coverage.

A UE-centric access which utilizes two levels of radio resource entityis described in FIG. 11. These two levels can be termed as “cell” and“beam”. These two terms are exemplary and used for illustrativepurposes. Other terms such as radio resource (RR) 1 and 2 can also beused. Additionally, the term “beam” as a radio resource unit is to bedifferentiated with, for instance, an analog beam used for beam sweepingin FIG. 10.

As shown in FIG. 11, the first RR level (termed “cell”) applies when aUE enters a network and therefore is engaged in an initial accessprocedure. In 1110, a UE 1111 is connected to cell 1112 after performingan initial access procedure which includes detecting the presence ofsynchronization signals. Synchronization signals can be used for coarsetiming and frequency acquisitions as well as detecting the cellidentification (cell ID) associated with the serving cell. In this firstlevel, the UE observes cell boundaries as different cells can beassociated with different cell IDs. In FIG. 11, one cell is associatedwith one TRP (in general, one cell can be associated with a plurality ofTRPs). Since cell ID is a MAC layer entity, initial access involves notonly physical layer procedure(s) (such as cell search viasynchronization signal acquisition) but also MAC layer procedure(s).

The second RR level (termed “beam”) applies when a UE is alreadyconnected to a cell and hence in the network. In this second level, a UE1111 can move within the network without observing cell boundaries asillustrated in FIG. 11. That is, UE mobility is handled on beam levelrather than cell level, where one cell can be associated with N beams (Ncan be 1 or >1). Unlike cell, however, beam is a physical layer entity.Therefore, UE mobility management is handled solely on physical layer.An example of UE mobility scenario based on the second level RR is givenin FIG. 11.

After the UE 1111 is associated with the serving cell 1112, the UE 1111is further associated with beam 1151. This is achieved by acquiring abeam or radio resource (RR) acquisition signal from which the UE canacquire a beam identity or identification. An example of beam or RRacquisition signal is a measurement reference signal (RS). Uponacquiring a beam (or RR) acquisition signal, the UE 1111 can report astatus to the network or an associated TRP. Examples of such reportinclude a measured beam power (or measurement RS power) or a set of atleast one recommended “beam identity (ID)” or “RR-ID”. Based on thisreport, the network or the associated TRP can assign a beam (as a radioresource) to the UE 1111 for data and control transmission. When the UE1111 moves to another cell, the boundary between the previous and thenext cells is neither observed nor visible to the UE 1111. Instead ofcell handover, the UE 1111 switches from beam 1151 to beam 1152. Such aseamless mobility is facilitated by the report from UE 711 to thenetwork or associated TRP—especially when the UE 1111 reports a set ofM>1 preferred beam identities by acquiring and measuring M beam (or RR)acquisition signals.

In the present disclosure, a “beam” can correspond to an RS resource orone port in RS or one port+one time unit in RS, whether the beam is asounding reference signal (SRS), CSI-RS, beam RS, measurement RS, or anyother type of RS.

In high frequency band system (e.g., >6 GHz system), the TRP and the UEcan be deployed with large number of antennas to relay on the high gainbeamforming to defeat the large path loss and signal blockage. A generalsystem configuration is that the TRP and UE have large number antennabut only one or a few TXRUs. So hybrid beamforming mechanism isutilized. Analog beams with different direction can be formulated on theantenna array that is connected to one TXRU. To get the best linkquality and coverage distance, the TRP and UE need to align the analogbeam directions for each particular downlink and uplink transmission.

In some embodiment, when a UE detects a beam failure event, the UE canbe requested to transmit beam recovery request and then monitor for thebeam recovery response from a TRP. If no proper response for the beamrecovery request is received within configured time duration T₀, the UEcan be configured to re-send the beam recovery request until a properbeam recovery response is received by the UE or the maximal number ofbeam recovery request transmission is achieved.

FIG. 12 illustrates an example beam recovery 1200 according toembodiments of the present disclosure. The embodiment of the beamrecovery 1200 illustrated in FIG. 12 is for illustration only. FIG. 12does not limit the scope of this disclosure to any particularimplementation

As shown in FIG. 12, a UE can transmit beam recovery request 1201 inslot n 1210. After sending the beam recovery request 1201 in slot n1210, the UE can be requested to monitor the gNB response during aconfigured beam recovery response window 1220. The beam recoveryresponse window can be N slot or T milliseconds that can be configuredby the NW. As illustrated in FIG. 12, the UE does not receive any properbeam recovery response during time window 1220. Then the UE can re-sendthe beam recovery request after the time window 1220. The UE sends beamrecovery request 1202 in slot m 1211 and monitors the beam recoveryresponse after sending beam recovery request 1202. Within the timewindow 1221, the UE receives a beam recovery response 1203 in slot l1212.

In some embodiments, the UE can be configured with one or more of thefollowing parameters by the NW. In one example, a length of time windowto monitor the beam recovery response from a gNB. It can be a number ofslot, N. It can be a length of time in milliseconds. The UE can berequested to monitor and receive beam recovery response within theconfigured time window after sending a beam recovery request. It can besignaled through system information, high layer signaling (e.g., RRC),MAC-CE or L1 signaling. In one example, a default value for the lengthof time window can be specified in the specification. The NW can signala new value e.g., through system information, high layer signaling,MAC-CE or L1 signaling to override the default value.

In another example, a maximum number of beam recovery requesttransmission, M_(max). When configured, the UE can be requested totransmit the beam recovery request message for up to M_(max) times for abeam failure event. It can be signaled through system information, highlayer signaling (e.g., RRC), MAC-CE or L1 signaling. In one example, adefault value for the length of time window can be specified in thespecification. The NW can signal a new value e.g., through systeminformation, high layer signaling, MAC-CE or L1 signaling to overridethe default value.

In yet another example, a second timer for the UE to transmit andre-transmit beam failure recovery request. If a second timer expires andthe UE does not receive any NW response to the beam failure recoveryrequest, the UE can be requested to abort the beam failure recoveryrequest transmission.

FIG. 13A illustrates a flow chart of a procedure 1300 for sending beamrecovery request according to embodiments of the present disclosure. Theembodiment of the procedure 1300 illustrated in FIG. 13A is forillustration only. FIG. 13A does not limit the scope of this disclosureto any particular implementation.

In one embodiment, the UE can be configured with both maximum number ofbeam failure recovery request and a second timer. The UE can re-transmitthe beam failure recovery request (if no NW response to any beam failurerecovery request is received) until maximum number is achieved or asecond timer expires.

In one embodiment, the UE can be configured with maximum number of beamfailure recovery request. The UE can re-transmit the beam failurerecovery request (if no NW response to any beam failure recovery requestis received) until maximum number is achieved.

In one embodiment, the UE can be configured with a second timer. The UEcan re-transmit the beam failure recovery request (if no NW response toany beam failure recovery request is received) until a second timerexpires.

A TRP configures by high layers a UE with a time window length (e.g., Nslots, T₀ milliseconds) within which the UE can be requested to monitorthe beam recovery response from the NW after sending a beam recoveryrequest at step 1310. A TRP configures by high layers a UE with amaximum number beam recovery request transmission, T₀, that indicatesthe maximal times a UE can send the beam recovery request after a beamfailure event is detected at step 1310. The UE detects the beam failureevent as configured by the NW at step 1320.

If a beam failure event is detected, the UE can determine to transmitbeam recovery request and initiate the number of beam recovery requesttransmission to zero at step 1320. The UE sends a beam recovery requestin a configured UL channel and then increases the number of beamrecovery request by one at step 1330. Then the UE begins to monitor thebeam recovery response from the NW. When the UE does not receive anybeam recovery response within the configured time window (e.g., N slots,T₀ milliseconds) in step 1340, the UE can check if the number of beamrecovery request transmission has achieved the configured transmissionnumber limit M_(max). When the UE determines the number of beam recoveryrequest transmission is less than the configured transmission numberlimit M_(max) in step 1350, the UE can re-send the beam recovery requeston a configured UL channel and then increase the number of beam recoveryrequest transmission by one in step 1330.

When the UE determines the number of beam recovery request transmissionis not less than the configured transmission number limit M_(max) instep 1350, the UE can abort the beam recovery request transmission andoperates the configured operations, e.g., initiating the RLF (radio linkfailure) procedure. When the UE receives any beam recovery responsewithin the configured time window (e.g., N slots, T₀ milliseconds) aftersending one beam recovery request in step 1340, the UE can abort thebeam recovery request transmission and operate accordingly based on thereceived beam recovery response, e.g., switching the beam to a indicatednew beam, reporting a beam state information in a scheduled ULtransmission, measuring some RS for beam management as configured.

FIG. 13B illustrates another flow chart of a procedure 1305 for sendingbeam recovery request according to embodiments of the presentdisclosure. The embodiment of the procedure 1305 illustrated in FIG. 13Bis for illustration only. FIG. 13B does not limit the scope of thisdisclosure to any particular implementation.

In one embodiment, the UE can be configured to continue monitoring thebeam failure detection RS to assess if a beam failure trigger conditionis met or not when the UE sends beam recovery request and monitors beamrecovery response as shown in FIG. 13B. The UE keeps monitoring the beamfailure RS to access the beam failure trigger condition in step 1380after the UE sends beam recovery request in step 1330. When the beamfailure trigger condition disappears, the UE can abort the beam recoveryrequest transmission in step 1390.

In one embodiment, the UE can be requested to monitor a beam failuredetection RS and measure the RSRP of some configured beam covered in thebeam failure RS to assess if a beam failure trigger condition is met. Inone method, the UE can be requested to measure the RSRP of NR-SSS in oneindicated NR-SS block. The gNB can configure a UE with one or more ofthe followings: the index of one NR-SS block, i; a RSRP threshold; atime duration T₁; and a number of measurement on NR-SS block, N₁.

The UE can be requested to measure the L1-RSRP of NR-SSS in theindicated NR-SS block index. In one example, when L1-RSRP of NR-SSS ofall NR-SS block index i within the time unit T₁ is less than aconfigured RSRP threshold, the UE can declare beam failure triggercondition is met. In one example, when L1-RSRP of NR-SSS of all NR-SSblock index i within N₁ consecutive NR-SS block burst sets is less thana configured RSRP threshold, the UE can declare beam failure triggercondition is met. In one example, when mean of L1-RSRP of NR-SSS of allNR-SS block index i within the time unit T₁ is less than a configuredRSRP threshold, the UE can declare beam failure trigger condition ismet.

In one example, when the mean L1-RSRP of NR-SSS of all NR-SS block indexi within N₁ consecutive NR-SS block burst sets is less than a configuredRSRP threshold, the UE can declare beam failure trigger condition ismet. In one example, when median of L1-RSRP of NR-SSS of all NR-SS blockindex i within the time unit T₁ is less than a configured RSRPthreshold, the UE can declare beam failure trigger condition is met. Inone example, when the median L1-RSRP of NR-SSS of all NR-SS block indexi within N₁ consecutive NR-SS block burst sets is less than a configuredRSRP threshold, the UE can declare beam failure trigger condition ismet.

Alternatively, the UE can be requested to measure the L1-RSRP of NR-PBCHsignal in one indicated NR-SS block i and apply the above embodiments todeclare the beam failure event. Alternatively, the UE can be requestedto measure the L1-RSRP of DMRS for NR-PBCH signal in one indicated NR-SSblock i and apply the above methods to declare the beam failure event.Alternatively, the UE can be requested to measure the sum L1-RSRP ofNR-SSS and NR-PBCH signal in one indicated NR-SS block i and apply theabove methods to declare the beam failure event.

In one method, the beam recovery request signal can include one or moreof the following component. In one example, the beam recovery requestsignal can include one bit information to indicate that beam failure isdetected; information to indicate that TRP Tx beam is failed;information to indicate that UE Rx beam is failed. In one example, thebeam recovery request signal can include information to indicate if anew candidate TRP Tx beam is determined by the UE.

In one example, the beam recovery request signal can include a TRP Txbeam recommended by the UE. It can be a NR-SS block index. It can be aCSI-RS resource ID. It can be a {CSI-RS resource ID, CSI-RS antenna portID or CSI-RS antenna port ID set index}.

In one example, the beam recovery request signal can include a requestfrom the UE to request UL assignment for a beam reporting; a requestfrom the UE to request the gNB to trigger aperiodic CSI-RS transmissionto allow the UE to refine Rx beams.

In one example, the beam recovery request signal can include UE'sidentity. It can be UE's RNTI. It can be implicitly indicated throughthe UL resource assigned to a UE to transmit beam recovery request. Itcan be jointly indicated through the UL resource assignment and signalscramble sequence.

In one method, the UE can assume to expect one or more of the followingmessages after sending a beam recovery request. In one example, the beamrecovery response is signaling indicating the UE to switch the beam ofcontrol channel to a new beam. The signaling can be RRC signaling,MAC-CE or L1 DCI signaling in common control channel. In one example,the beam recovery response is that the UE decodes DCI in control channelby assuming the gNB uses the recommended beam in the beam recoveryrequest message within the configured time window. In one example, thebeam recovery response is a dedicated acknowledge message transmitted inDCI or MAC-CE to inform the UE that the beam recovery request isreceived successfully by the NW. In one example, the beam recoveryresponse is that the UE receives a UL NR-PUSCH assignment. In oneexample, the beam recovery response is that the UE receives the triggermessage of aperiodic CSI-RS transmission or semi-persistenttransmission.

In some embodiments, a UE can be configured with a signal sequence and aUL channel. The UE can be request to send the configured signal sequenceon the configured UL channel when beam recovery request triggercondition is met. After sending the configured signal sequence, the UEcan be configured to receive a DCI scrambled with this UE's RNTI withinN slots. If no DCI scrambled with this UE's RNTI is received within Nslots, the UE can re-send the configured signal sequence.

A UE can be configured to monitor M≥1 BPLs (beam pair links) on thePDCCH. Each BPL corresponds to a pair of one TRP Tx beam and one UE Rxbeam. Based on BPL identification, the UE can calculate the Rx beam thatmay be used to buffer one PDCCH. The UE can be configured with M≥1 BPLsat a slot-level or OFDM symbol-level. If at slot-level, the UE can beconfigured with different BPLs at different slots. If at OFDMsymbol-level, the UE can be configured with different BPL at differentOFDM symbols in the PDCCH region at one slot.

When the UE is configured with M≥1 BPLs to monitor the PDCCH, the UE canbe requested to transmit beam failure recovery request message if somecondition is met. The condition can be one of more of the followings. Inone example, the condition can be the L1 RSRP measurement of all Mconfigured BPL is below a configured RSRP threshold for configured timeduration, e.g., N slots and a new candidate beam is identified.

In one example, the condition can be out of configured M≥1 BPLs, one BPLis defined as the primary BPL. The L1 RSRP measurement of primary BPL isbelow a configured RSRP threshold for configured time duration and newcandidate beam is identified.

In one example, the condition can be the L1 RSRP measurement of primaryBPL is below a configured RSRP threshold for configured time duration.

In one example, the condition can be the L1 RSRP measurement of one ormore but <M BPLs is below a configured RSRP threshold for a configuredtime duration.

In one embodiment, the UE can be configured with an L1 RSRP thresholdand time duration for each BPL separately.

The UE can be configured to monitor the L1 RSRP of all M configured BPL.In one embodiment, the UE can be requested to monitor the L1 RSRP of oneor more than one CSI-RS resources in a periodic CSI-RS orsemi-persistent CSI-RS transmission. In one example, the TRP can signala subset of CSI-RS resource indices or the index of CSI-RS resourceports/CSI-RS resource indices and the UE can be requested to monitor theL1 RSRP of those CSI-RS resources or CSI-RS resource ports. In oneexample, the TRP can signal a subset of SS-block time indices and the UEcan be requested to monitor the L1 RSRP of signals in those SS-blocks.

The signals in SS blocks can be NR-SSS, NR-PBCH, DMRS to NR-PBCH or thecombination of these signals. In one embodiment, the UE can be requestedto monitor the corresponding CSI-RS resource, CSI-RS ports or SS-blockwhen the UE is configured with one BPL to monitor the PDCCH. When the UEis configured with M BPL to monitor the PDCCH, the UE can be requestedto calculate the corresponding CSI-RS resource, CSI-RS ports or SS blockfor each configured BPL and then monitor the L1 RSRP. When the RSresource corresponding to one configured BPL is updated, the UE can berequested to monitor the new RS resource.

In one embodiment, the UE can be requested to calculate the Tx power ofbeam recovery request based on the path loss measured from the selectednew candidate beam. The Tx power can be calculated by:

${P_{{BR},c,k}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{{P_{{BR\_ OFFSET},c,k}(m)} + {10\log_{10}( {M_{{BR},c}(i)} )} + {P_{O,c,k}(j)} + {{\alpha_{c,k}(j)} \cdot {PL}_{c,k}} + {f_{c,k}(i)}}\end{Bmatrix}.}}$

The path loss PL_(c,k) can be measured from the RS that carries the newcandidate beam selected by the UE. The parameters Po and α can beconfigured specifically for beam recovery request by the NW. Theparameters Po and α can be re-used of the parameters for PUSCH, SRS,PUCCH or PRACH transmission.

In one embodiment, the UE can increase the Tx power of beam recoveryrequest transmission in the re-transmission of beam recovery request.

In one embodiment, the UE may re-calculate the Tx power if the UEchanges the selection of new candidate beam in the re-transmission ofbeam recovery request.

The UE can be configured to trigger an event report if one or more butnot all of those M configured BPLs have L1 RSRP being below someconfigured threshold for configured time duration. In one example, theUE can report an event in PUCCH and the message can include one or moreof the followings: an indication of some BPL(s) is failed; and theidentification information of one or more BPLs. After sending the eventreport, the UE can be requested to monitor the rest of BPL for the eventresponse from the TRP.

In some embodiments, a UE can be configured to measure the beam qualityof one configured periodic RS resource and reports the measurementresults to upper layer. A UE can be configured with a first beam qualitythreshold, a second beam quality threshold, a first beam qualitymeasurement time duration, and a second beam quality measurement timeduration.

In one embodiment, a UE can be configured with a first beam qualitythreshold, a number threshold and a RS resource (e.g., one CSI-RSresource, one NR-SS block index, one CSI-RS resource+port index). The UEcan be configured to measure the L1 RSRP or L1 RSRQ of each RS resourcetransmission and then compare the L1 RSRP or L1 RSRQ with the configuredfirst beam quality threshold. If the measured L1 RSRP or L1 RSRQ isbelow the first beam quality threshold, the UE can report abeam-link-out-of-sync event to the upper layer.

In one example, if the number of consecutive beam-link-out-of-syncevents is above a number threshold, the UE can declare the beam failureis detected on configured RS resource. If the configured RS resource isNR-SS block, the UE can be configured to measure the L1-RSRP or L1-RSRQfrom NR-SSS signal in the configured NR-SS block, or NR-SSS and DMRS forPBCH in the configured NR-SS block. If the configured RS resource is oneCSI-RS resource, the UE can be configured to measure the L1-RSRP orL1-RSRQ of a first antenna port in the configured CSI-RS resource andthe UE can be configured to measure more than one or all antenna portsin CSI-RS resource and then sum or average the L1-RSRP of those antennaports.

In one example, the UE can be configured to measure the SINR-like orCQI-like metric on configured RS resource. The UE can be configured tomeasure the SINR-like or CQI-like metric by assuming one PDCCH signal istransmitted on the time-frequency resource used by the configured RSresource. The UE can be configured with the transmit power offsetbetween the PDCCH signal and the configured RS resource. The UE can berequested to measure the SINR-like or CQI-like by applying the transmitpower offset and also the transmit scheme assumed for the PDCCH channel.

The UE can be requested to measure the SINR-like or CQI-like metric ofeach RS resource transmission instance and then compare theSINR-like/CQI-like metric with a first beam quality. If theSINR-like/CQI-like metric is below a first beam quality, the UE canreport beam-link-out-of-sync event to the upper layer. In one example,if the number of consecutive beam-link-out-of-sync events is above anumber threshold, the UE can declare the beam failure is detected onconfigured RS resource.

In one example, the UE can be requested to assume the configured RS toestimate the channel by assuming the configured RS as DMRS to measurethe SINR-like metric or CQI-like metric. If the RS has more antennaports than the DMRS of corresponding PDCCH, the UE can be configured toassume some precoding is applied to the configured RS first before theUE measure the CQI-like or SINR-like metric.

In one embodiment, the UE can be configured with two number thresholds:a first number threshold and a second number threshold. The UE candeclare the beam failure if the number beam-link-out-of-sync is above afirst number threshold within the latest a second number threshold L1metric measurement reporting from L1.

In one embodiment, the UE can be configured with a third numberthreshold and a ratio threshold. The UE can declare the beam failure ifthe ratio of beam-link-out-of-sync is above a ratio threshold within thelatest a third number threshold L1 metric measurement reporting from L1.

In one embodiment, the UE can be configured to monitor the beam qualityof multiple RS resources. In one example, the UE can be configured tomeasure the beam quality of each CSI-RS resources of multiple indicatedCSI-RS resource. In one example the UE can configured to measure thebeam quality of each NR-SS block of multiple indicated NR-SS blocks.

In one embodiment, the UE can be configured with a first beam qualitythreshold (e.g., L1 RSRP value, L1 RSRQ value, SINR, CQI) for eachindicated RS resource. Then the UE can be configured to measure the beamquality (as configured) of each transmission instance of each indicatesRS resource and then compare each measured beam quality with thecorresponding configured a first beam quality threshold. If one measuredbeam quality is below the configured a first beam quality threshold, abeam-link-out-sync event can be claimed for that RS resource. The UE canalso be configured with a threshold for event number for each ofindicated RS resource. If the number of consecutive beam-link-out-syncis larger than the configured threshold for event number, thecorresponding RS resource (and corresponding) can be declared as beamfailure.

In one embodiment, the UE can be configured with one a first beamquality threshold and a threshold for event number that are used for allindicated RS resources.

In one embodiment, one UE can be configured with one or more RS resourceindices the UE to measure and monitor the beam failure for one or moreBPL (beam pair link) for PDCCH. The PDCCH can be UE-specific PDCCH. ThePDCCH can be UE-group-common PDCCH.

In one embodiment, the UE can be configured with one or more than oneCSI-RS resource indicators and also the mapping between indicated CSI-RSresource indicators and the BPLs used for PDCCH transmission. If the UEdeclare the beam quality of one CSI-RS resource is failed, the UE canassume the beam failure event of the corresponding BPL has occurred.

In one embodiment, the UE can be configured with one or more than oneNR-SS block indicators and also the mapping between indicated NR-SSblock indicators and the BPLs used for PDCCH transmission. If the UEdeclares the beam quality of one NR-SS block is failed, the UE canassume the beam failure event of the corresponding BPL has occurred.

In one embodiment, the UE can be configured with one or more than oneNR-SS block indicators and one or more CSI-RS resource indicators andalso the mapping between indicated NR-SS block indicators/CSI-RSresource indicators and the BPLs used for PDCCH transmission. If the UEdeclare the beam quality of one NR-SS block/CSI-RS resource is failed,the UE can assume the beam failure event of the corresponding BPL hasoccurred. The aforementioned information of embodiments can be signaledby RRC signaling, MAC-CE signaling or DCI signaling.

In one embodiment, the UE can be requested to calculate the CSI-RSresource indicator, CSI-RS resource/port index or NR-SS block indexbased on the configured BPLs for monitoring PDCCH transmission. In oneexample, the UE can be configured with one or more BPLs for PDCCHtransmission, The UE can be requested to calculate the RS resource indexbased on each configured BPL and then monitor the calculated RSresources for the beam failure event of corresponding BPL.

In one embodiment, the UE can be requested to calculate the RS resourceindex based on the configured BPLs for monitoring PDCCH transmission.The UE can also be configured to monitor the beam failure event for asubset of the configured BPLs.

In some embodiments, a UE can be configured to identify one or more newcandidate beam from a configured RS setting. The UE can be configuredwith: a set of RS resources: a set of multiple periodic CSI-RS resources(e.g., a set of multiple NR-SS blocks); a first beam quality threshold(e.g., can be threshold for L1 RSRP, L1 RSRQ, SINR, CQI, and CSI);and/or a threshold for measurement number (e.g., a number ofmeasurement, a metric of time, for example milliseconds).

In one embodiment, a UE can be configured with a first beam qualitythreshold, a number threshold and a RS resource (e.g., one CSI-RSresource, one NR-SS block index, one CSI-RS resource+port index). The UEcan be configured to measure the L1 RSRP or L1 RSRQ of each RS resourcetransmission and then compare the L1 RSRP or L1 RSRQ with the configuredfirst beam quality threshold. If one measured L1 RSRP or L1 RSRQ isabove the first beam quality threshold, the UE can report abeam-candidate event to the upper layer.

In one example, if the number of consecutive beam-candidate events isabove a number threshold, the UE can declare a new candidate beam isdetected on configured RS resource. If the configured RS resource isNR-SS block, the UE can be configured to measure the L1-RSRP or L1-RSRQfrom NR-SSS signal in the configured NR-SS block, or NR-SSS and DMRS forPBCH in the configured NR-SS block. If the configured RS resource is oneCSI-RS resource, the UE can be configured to measure the L1-RSRP orL1-RSRQ of a first antenna port in the configured CSI-RS resource andthe UE can be configured to measure more than one or all antenna portsin CSI-RS resource and then sum or average the L1-RSRP of those antennaports.

In one example, the UE can be configured to measure the SINR-like orCQI-like metric on configured RS resource. The UE can be configured tomeasure the SINR-like or CQI-like metric by assuming one PDCCH signal istransmitted on the time-frequency resource used by the configured RSresource. The UE can be configured with the transmit power offsetbetween the PDCCH signal and the configured RS resource. The UE can berequested to measure the SINR-like or CQI-like by applying the transmitpower offset and also the transmit scheme assumed for the PDCCH channel.The UE can be requested to measure the SINR-like or CQI-like metric ofeach RS resource transmission instance and then compare theSINR-like/CQI-like metric with a first beam quality. If theSINR-like/CQI-like metric is above a first beam quality, the UE canreport beam-candidate event to the upper layer.

In one example, if the number of consecutive beam-candidate events isabove a number threshold, the UE can declare a new candidate beam isdetected on that RS resource. In one example, the UE can be requested toassume the configured RS to estimate the channel by assuming theconfigured RS as DMRS to measure the SINR-like metric or CQI-likemetric. If the RS has more antenna ports than the DMRS of correspondingPDCCH, the UE can be configured to assume some precoding is applied tothe configured RS first before the UE measure the CQI-like or SINR-likemetric.

In one embodiment, the UE can be configured with two number thresholds:a first number threshold and a second number threshold. The UE candeclare a new candidate beam if the number of beam-candidate is above afirst number threshold within the latest a second number threshold L1metric measurement reporting from L1.

In one embodiment, the UE can be configured with a third numberthreshold and a ratio threshold. The UE can declare a new candidate beamif the ratio of beam-candidate is above a ratio threshold within thelatest a third number threshold L1 metric measurement reporting from L1.

A UE can be requested to measure RS resource transmission and claim beamfailure according one or more of the following embodiments.

In one embodiment, the UE can be requested to measure the L1-RSRP orL1-RSRQ of each RS transmission instance of all N consecutive RStransmission instances (during one indicated time duration). The UE cancompare the L1-RSRP or L1-RSRQ of each RS transmission instance with aconfigured threshold. The UE can claim the beam failure of beam that isassociated with the measured RS resource if the L1-RSRP or L1-RSRQ ofall N RS transmission instances is below the configured threshold.

In another embodiment, the UE can be requested to measure the L1-RSRP orL1-RSRQ of each RS transmission instance of all N consecutive RStransmission instances (during one indicated time duration). The UE cancompare the L1-RSRP or L1-RSRQ of each RS transmission instance with aconfigured threshold. The UE can claim the beam failure of beam that isassociated with the measured RS resource if the mean or median ofL1-RSRP or L1-RSRQ of all N RS transmission instances is below theconfigured threshold.

In yet another embodiment, the UE can be requested to measure theL1-RSRP or L1-RSRQ of each RS transmission instance of all N consecutiveRS transmission instances (during one indicated time duration). The UEcan compare the L1-RSRP or L1-RSRQ of each RS transmission instance witha configured threshold. The UE can claim the beam failure of beam thatis associated with the measured RS resource if the percentage of RStransmission instance whose L1-RSRP or L1-RSRQ is below the configuredthreshold is above some configured percentage threshold.

In yet another embodiment, the UE can be requested to measure the SINRor CQI of each RS transmission instance of all N consecutive RStransmission instances (during one indicated time duration). The UE cancompare the SINR or CQI of each RS transmission instance with aconfigured threshold. The UE can claim the beam failure of beam that isassociated with the measured RS resource if the SINR or CQI of all N RStransmission instances is below the configured threshold.

In yet another embodiment, the UE can be requested to measure the SINRor CQI of each RS transmission instance of all N consecutive RStransmission instances (during one indicated time duration). The UE cancompare the SINR or CQI of each RS transmission instance with aconfigured threshold. The UE can claim the beam failure of beam that isassociated with the measured RS resource if the mean or median of SINRor CQI of all N RS transmission instances is below the configuredthreshold.

In yet another embodiment, the UE can be requested to measure the SINRor CQI of each RS transmission instance of all N consecutive RStransmission instances (during one indicated time duration). The UE cancompare the SINR or CQI of each RS transmission instance with aconfigured threshold. The UE can claim the beam failure of beam that isassociated with the measured RS resource if the percentage of RStransmission instance whose SINR or CQI is below the configuredthreshold is above some configured percentage threshold.

In some embodiments, a UE can be configured to measure one RS resourcetransmission for the beam failure detection of BPL (beam pair link) thatis configured for PDCCH transmission. The UE can be requested to use thesame Rx beam to measure the beam quality of one RS resource transmissionas the Rx beam used to receive the PDCCH that is configured with the BPLassociating with the configured RS resource transmission.

In one embodiment, the UE can be configured with RS resource for beamfailure detection through an implicit method. A UE can be configuredwith one BPL or spatial quasi co-located (QCL) assumption informationfor one or more CORESET of PDCCH. The UE can be requested to calculatethe Rx beam that may be used to receive the corresponding CORESET basedon indicated BPL or spatial QCL assumption. The UE can also be requestedto calculate the index of one RS resource that corresponds to the BPL orspatial QCL assumption. In one example, the RS resource used for beamfailure detection is CSI-RS resource. In another example, the RSresource used for beam failure detection is NR-SS block. The UE can berequested to calculate the index of one RS resource that corresponds toone indicated BPL or spatial QCL assumption information and then beginto measure/monitor the transmission instance of calculated RS resourcebased on one or more of the method described above.

In one embodiment, the UE can be configured with one RS resource forbeam failure detection for one indicated BPL for PDCCH transmissionthrough an explicit method. In one example, the UE can be configuredwith one CSI-RS resource or one NR-SS block index and the UE can berequested to use measure the quality of configured CSI-RS resource orNR-SS block for the first configured BPL for PDCCH. In one example, theUE can be configured with one or more CSI-RS resources or NR-SS blockindices and a tag index for each configured RS resource. The UE can berequested to calculate the BPL index or corresponding spatial QCLassumption based on each indicated tag index and then the UE can berequested to measure each configured RS resource for the beam failuredetection for the BPL or spatial QCL assumption corresponding to the tagindex associated with that RS resource. The UE can measure and monitoreach configured RS resource for the beam failure detection forcorresponding BPL according to one or more of method described above.

In one embodiment, the UE can be configured with spatial QCLconfiguration for UE-specific PDCCH by signaling one or moretransmission configuration indication (TCI) state(s). The UE can beconfigured with a TCI state for each CORESET. The UE can be configuredwith TCI state for each search space. The UE can be configured with oneor more than one TCI states for UE-specific PDCCH. The UE can beconfigured to declare beam failure if all the configured TCI states arefailed. The UE can be configured to detect the failure of each TCI stateas follows.

In one example, one TCI state can be configured for one or more CORSET(or search space). For one configured TCI state j, the UE can berequested to calculate the ID of DL RS that is used for the purpose ofspatial QCL. The DL RS can be SSB (SS block), CSI-RS (periodic,semi-persistent, or aperiodic). The UE can be requested to monitor thecalculated DL RS to detect the beam failure of TCI state j. The UE canbe requested to use the methods described in this disclosure to measurethe calculate DL RS and the detect beam failure.

In another example, the UE can be configured with M TCI states {a₁, a₂,. . . , a_(M)} for spatial QCL for UE-specific PDCCH. For one TCI statea_(i) in {a₁, a₂, . . . , a_(M)}, the UE can be configured with a indexof DL RS and that DL RS resource can be configured to be associated withTCI state a_(i), and the UE can be requested to measure/monitor this DLRS resource to detect the beam failure of TCI state a_(i). Suchassociation configuration can be signaled/configured through high layersignaling, MAC-CE and/or physical layer signaling (e.g., DCI).

In one embodiment, a UE can be configured to use one or more CSI-RSresource and/or NR-SS blocks to identify new beam candidate and the UEcan recommend the identified new beam candidate to the TRP when beamfailure is detected.

In one embodiment, the UE can be requested to measure the L1-RSRP orL1-RSRQ of transmission instances of each CSI-RS resource or NR-SS blockin the configured CSI-RS resource/NR-SS blocks for new beamidentification. The UE can assume one CSI-RS or NR-SS block as new beamcandidate if one or more of the following conditions are met. In oneexample, the mean or median L1-RSRP or L1-RSRQ of one CSI-RS resourcetransmission instances or NR-SS block transmission instances is abovesome configured threshold. In another example, the L1-RSRP or L1-RSRQ ofall N consecutive transmission instances of one CSI-RS resource or NR-SSblock (or within one time window duration) is above some configuredthreshold. In yet another example, the percentage of transmissioninstances of all N consecutive transmission instances of one CSI-RSresource or NR-SS block (or within one time window duration) whoseL1-RSRP or L1-RSRQ being above some configured threshold is above someconfigured percentage threshold.

In one embodiment, the UE can be requested to measure the SINR or CQI oftransmission instances of each CSI-RS resource or NR-SS block in theconfigured CSI-RS resource/NR-SS blocks for new beam identification. TheUE can assume one CSI-RS or NR-SS block as new beam candidate if one ormore of the following conditions are met. In one example, the mean ormedian SINR or CQI of one CSI-RS resource transmission instances orNR-SS block transmission instances is above some configured threshold.In another example, the SINR or CQI of all N consecutive transmissioninstances of one CSI-RS resource or NR-SS block (or within one timewindow duration) is above some configured threshold. In yet anotherexample, the percentage of transmission instances of all N consecutivetransmission instances of one CSI-RS resource or NR-SS block (or withinone time window duration) whose SINR or CQI being above some configuredthreshold is above some configured percentage threshold.

If more than one CSI-RS resources (or SSBs) are associated with the samededicated UL channel resource as configuration to the UE, the UE can berequested to select the dedicated UL channel resource for beam recoveryrequest transmission if one of the associated CSI-RS resources (or SSBs)meet the new beam identification condition. If more than one CSI-RSresources (or SSBs) are associated with the same dedicated UL channelresource as configuration to the UE, the UE can be requested to selectthat dedicated UL channel resource for beam recovery requesttransmission if the averaged RSRP/CQI/SINR of all the associated CSI-RSresources (or SSBs) meet the new beam identification condition. If morethan one CSI-RS resources (or SSBs) are associated with the samededicated UL channel resource as configuration to the UE, the UE can berequested to select that dedicated UL channel resource for beam recoveryrequest transmission if the CSI-RS resource (SSB) with lowest (orhighest) index among all associated CSI-RS resources (or SSBs) meets thenew beam identification condition.

In one embodiment, the UE can be configured with both a set of CSI-RSresources and a set of SS blocks (SSB) to identify the new candidatebeam for beam recovery request. One-bit field in high layer signalingcan be used to indicate the UE that SS blocks are configured for newcandidate beam identification. The UE can be requested to use theconfiguration of actually transmitted SSBs signaling by RMSI and/or RRCsignaling.

If a first CSI-RS resource and a second SSB are associated with the samededicated UL channel resource, the UE can choose that UL channelresource for beam recovery request transmission only if both a firstCSI-RS resource and a second SSB can meet the new candidate beamselection condition. If a first CSI-RS resource and a second SSB areassociated with the same dedicated UL channel resource, the UE canchoose that UL channel resource for beam recovery request transmissiononly if the UE can identify both a first CSI-RS resource and a secondSSB as a new beam. If a first CSI-RS resource and a second SSB areassociated with third dedicated UL channel resource but a first CSI-RSresource is not QCLed with a second SSB as configured by the gNB, the UEcan assume there is an error case and ignore the association between afirst CSI-RS resource and a third UL channel resource but only assumethe association between a second SSB and a third UL channel resource.

In one embodiment, in the configuration for beam failure recoveryconfiguration, a CSI-RS resource index a and a SSB index b are includedin Candidate-Beam-RS-List. A CSI-RS resource index is spatial QCLed withSSB index b. SSB index b is associated with a first PRACH resource inthe configuration for beam failure recovery configuration. The UE canchoose a first PRACH resource for beam failure recovery requesttransmission (i.e. link reconfiguration request transmission) if theL1-RSRP measured from SSB index b meets the new candidate beamidentification condition or if the L1-RSRP of both SSB index b andCSI-RS a meet the new candidate beam identification.

In one embodiment, a UE can be configured with a CORESET that isdedicated for monitoring gNB's response to beam failure recoveryrequest. In one method, the UE can be configured with a first CORESETand a second set of CORESETs. The UE can be requested to monitor theCORESETS in a second set of CORESET for normal downlink and uplinktransmission. After the UE sends one beam failure recovery request, theUE can be requested to monitor a first CORESET for the response to beamfailure recovery request. The response from NW to the beam failurerecovery request can be implicit and/or explicit.

In one embodiment, the response from NW can be implicitly indicated bythat a DCI (or control singling message) is correctly decoded by the UEin a first CORESET. The UE can be configured to claim that a responsefrom NW for the beam failure recovery request is correctly received if aDCI is correctly decoded by the UE in a first CORESET.

In one embodiment of explicit scheme, one or more of the following canbe considered as NW response to the beam failure recovery request. Inone example, one special DCI type is considered to indicate the NWresponse to the beam failure recovery request. In another example, theDCI is scrambled by a special RNTI, e.g., BR-RNTI BFR-RNTI. That specialRNTI can be configured UE-specifically or cell-specially orpre-configured. In yet another example, the value of one bit field inDCI is considered to indicate the NW response to the beam failurerecovery request. In yet another example, the presence/absence of onebit field in DCI is considered to indicate the NW response to the beamfailure recovery request. In yet another example, a dedicated NWresponse message is transmitted in PDSCH scheduled by the DCI sent in afirst CORESET.

In one embodiment, when a new BPL (e.g., a Tx beam) is indicated in beamfailure recovery request, the UE can be requested to monitor a firstCORESET by assuming the DMRS in a first CORESET is spatial QCLed to thenew BPL indicated in beam failure recovery request.

In one embodiment, after one UE sends one beam failure recovery request,the UE can begin to monitor a first CORESET that is dedicatedlyconfigured for gNB response for beam failure recovery request. The UEcan assume to stop monitoring a first CORESET after a valid DCIscrambled by this UE's C-RNTI is correctly received in a first CORESET.

In one embodiment, one gNB can signal one MAC-CE to indicate the UE tostop monitoring a first CORESET and after receiving that MAC-CE, the UEcan assume to stop monitoring a first CORESET. In one example, one UEsends one beam failure recovery request at slot n. The UE can begin tomonitor a first CORESET at slot n+offset. At slot m, the UE receives aMAC-CE or high layer signaling to indicate the UE to stop monitoring afirst CORESET. Then the UE stops monitoring a first CORESET and the UEcan resume monitoring a first CORESET after a new beam failure recoveryrequest is sent.

In one embodiment, the UE can begin to monitor a first CORESET that isdedicated configured for gNB response to the beam failure recoveryrequest. The UE can stop monitoring a first CORESET after the UE hasreceived signaling from the gNB to configure the spatial QCL assumptionfor all the PDCCH which is included for beam failure recovery request.In one example, one UE is configured with K PDCCHs. The UE detects thebeams of all K PDCCH are failed so the UE transmit a beam failurerecovery request at slot n. The UE can begin to monitor a first CORESETat slot n+offset. At some slots after n+offset, the UE can receive theMAC-CE or high layer signaling to configure or indicate the spatial QCLreference for one or more of those K PDCCHs. After the UE receives thesignaling to configure or indicate the spatial QCL reference for allthose K PDCCHs, the UE can stop monitoring a first CORESET and the UEcan assume monitoring a first CORESET after a new beam failure recoveryrequest is sent.

In one embodiment, a UE can be configured with multiple BPL to monitorthe PDCCH. In the beam failure recovery request, the UE can indicate theevent of beam failure and the index of BPLs that were detected beamfailure (for example, the UE can use a bitmap to indicate the beamfailure of each BPL. Each bit in the bitmap corresponds to oneconfigured BPL and the value of that bit being 1 (or 0) can indicate thecorresponding BPL is detected beam failure). After sending the beamfailure recovery request, the UE can monitor a first CORESET by assumingthe DMRS in a first CORESET can be spatial QCLed to one of the unfailedBPLs. In one example, the UE can assume the DMRS in a first CORESET canbe spatial QCLed to the BPL that is not failed and has the lowest indexamong all the unfailed BPLs. In one example, the UE can assume the DMRSin a first CORESET can be spatial QCLed to the BPL that is not failedand has the largest index among all the unfailed BPLs.

In one embodiment, the UE can be requested to monitor one or more of theconfigured CORESET that is configured to normal downlink and uplinktransmission for NW response to the beam failure recovery request.

In one embodiment, the UE can be configured with one or more CORESET{c1, c2, . . . , cL} and with one single BPL for PDCCH. Then the UE maymonitor all the configured CORESETs with the same configured BPL. Ifthat BPL is detected beam failure, the UE can be requested to monitorone or more of configured CORESETs {c1, c2, . . . , cL} for NW response.The UE can assume the DMRS of monitored CORESETS chosen among {c1, c2, .. . , cL} is spatial QCLed to the new Tx beam indicated by beam failurerecovery request.

In one embodiment, the UE can be requested to monitor all the configuredCORESET {c1, c2, . . . , cL}. In one example, the UE can be requested tomonitor a subset of configured CORESETs {c1, c2, . . . , cL}. In oneexample, the UE can be requested to monitor one particular from theconfigured CORESETs {c1, c2, . . . , cL}.

In one embodiment, the UE can be configured with one or more CORESET{c1, c2, . . . , cL} and with multiple BPLs for PDCCH. Then the UE maymonitor all the configured CORESETs with the same or differentconfigured BPLs. If all the BPLs are detected beam failure, the UE canbe requested to monitor one or more of configured CORESETs {c1, c2, . .. , cL} for NW response. The UE can assume the DMRS of monitoredCORESETS chosen among {c1, c2, . . . , cL} is spatial QCLed to the newTx beam indicated by beam failure recovery request.

In one example, the UE can be requested to monitor all the configuredCORESET {c1, c2, . . . , cL}. In one example, the UE can be requested tomonitor a subset of configured CORESETs {c1, c2, . . . , cL}. In oneexample, the UE can be requested to monitor one particular from theconfigured CORESETs {c1, c2, . . . , cL}.

In one embodiment, the UE can be configured with one or more CORESET{c1, c2, . . . , cL} and with multiple BPLs for PDCCH. Then the UE maymonitor all the configured CORESETs with the same or differentconfigured BPLs. If not all the BPLs are detected beam failure but onlya subset of configured BPLs are detected beam failure, the UE can berequested to monitor one or more of configured CORESETs {c1, c2, . . . ,cL} for NW response. In one example, the UE can be requested to monitorthose CORESETs whose corresponding configured BPL are not detected beamfailure for NW response. The UE can assume that the DMRS of thoseCORESETs are still spatial QCLed to the corresponding configured BPL. Inone example, the UE can be requested to monitor only one CORESET amongthe CORESETs whose corresponding configured BPL are not detected beamfailure. In one example, the UE can be requested to monitor a subset ofthose CORESETs whose corresponding configured BPL are not detected beamfailure.

In one embodiment, the UE can be requested to expect only fall back DCIsin the control resource configured through higher layer parameterBeam-failure-recovery-Response-CORESET. The fall back DCI can be UL DCIformat 0_0 and DL DCI format 1_0.

In one embodiment, the UE can be configured to assume only particularDCI format(s) are transmitted in the control resource configured throughhigher layer parameter Beam-failure-recovery-Response-CORESET. In oneexample, the UE can be configured to assume only DCI format 0_0 and DCIformat 1_0 are transmitted in control resource configured through higherlayer parameter Beam-failure-recovery-Response-CORESET.

In one embodiment, once the UE receive gNB's response to one beamfailure recovery request (i.e., the PRACH transmission for linkreconfiguration request), the UE can be requested to monitor some ofthose old CORESETs or monitor only particular DCI format in those oldCORESETs. The UE can be requested to assume such behavior on those oldCORESET until (1) the TCI state used as QCL reference for those CORESETare re-configured and (2) control resource set(s) are re-configured. Oneor more of the following embodiments can be used for UE to monitor thoseold CORESETs after receiving gNB response.

In one embodiment, a UE can be configured with a few control resourcesets {CORESET1, CORESET2, . . . } for monitoring PDCCH. When the UEdetects beam failure on those control resource sets {CORESET1, CORESET2,. . . }, the UE can start the beam failure recovery procedure. After theUE receives valid a DCI formats with CRC scrambled by C-RNTI throughmonitoring PDCCH in the control resource configured by higher layerparameter Beam-failure-recovery-Response-CORESET, the UE can berequested to monitor DCI format 1_0 and 0_0 in the PDCCH in controlresource sets {CORESET1, CORESET2, . . . }.

In another embodiment, a UE can be configured with a few controlresource sets {CORESET1, CORESET2, . . . } for monitoring PDCCH. Whenthe UE detects beam failure on those control resource sets {CORESET1,CORESET2, . . . }, the UE can start the beam failure recovery procedure.After the UE receives valid a DCI formats with CRC scrambled by C-RNTIthrough monitoring PDCCH in the control resource configured by higherlayer parameter Beam-failure-recovery-Response-CORESET, the UE can berequested to only monitor PDCCH in one control sets of those old controlresource sets {CORESET1, CORESET2, . . . }. In one example, the UE canbe requested to only monitor PDCCH in the control resource set withlowest CORESET-ID among those old control resource sets {CORESET1,CORESET2, . . . }.

In yet another embodiment, a UE can be configured with a few controlresource sets {CORESET1, CORESET2, . . . } for monitoring PDCCH. Whenthe UE detects beam failure on those control resource sets {CORESET1,CORESET2, . . . }, the UE can start the beam failure recovery procedure.After the UE receives valid a DCI formats with CRC scrambled by C-RNTIthrough monitoring PDCCH in the control resource configured by higherlayer parameter Beam-failure-recovery-Response-CORESET, the UE can berequested to only monitor PDCCH in one control sets of those old controlresource sets {CORESET1, CORESET2, . . . } and only monitor particularDCI format(s). In one example, the UE can be requested to only monitorPDCCH in the control resource set with lowest CORESET-ID among those oldcontrol resource sets {CORESET1, CORESET2, . . . } and the UE can berequested to only DCI format 0_0 and DCI format 1_0 in that controlresource set.

In some embodiments, a UE can be configured with two UL channels forbeam recovery request transmission, a first UL channel and a second ULchannel.

In one example, a first UL channel can be a UL channel without beamsweeping operation. An example of a first UL channel is NR-PUCCHchannel. A second UL channel can be a UL channel that supports TRP Rxbeam sweeping and/or UE Tx beam sweeping. An example of a second ULchannel is NR-PRACH channel. The use case for a first UL channel is whenthe beam failure event is detected in DL connection and the ULconnection can still support reliable PUCCH transmission. The use casefor a second UL channel is when beam failure event is detected in DLconnection and the TRP Rx beam/UE Rx beam for UL transmission aremisaligned too.

In another example, a first UL channel can be a contention-free ULchannel for beam recovery request transmission. A second UL channel canbe a contention-based UL channel for beam recovery request transmission.In a contention-free UL channel, one UE can be configured with adedicated resource, for example, one dedicated preamble sequence, andthe UE can transmit the indicated preamble in one selectedtime-frequency resource for the beam recovery request. IN acontention-based UL channel, one UE can be configured with a subset ofdedicated resources for beam recovery request, for example, a subset ofpreamble sequences and the UE can be requested to select one from thatsubset for beam recovery request transmission.

The UE is configured with a first transmit beam recovery request on afirst UL channel when a beam failure trigger condition is met (e.g.,through measuring beam failure detection RS, e.g., NR-SS block or CSI-RSfor beam management). When the UE does not receive beam recoveryresponse for the beam recovery request sent on a first UL channel, theUE can be configured to transmit beam recovery request on a second ULchannel to report the same detected beam failure event.

FIG. 14 illustrates a flow chart of a procedure 1400 for sending beamrecovery request on a first UL channel and a second channel n exampleaccording to embodiments of the present disclosure. The embodiment ofthe procedure 1400 illustrated in FIG. 14 is for illustration only. FIG.14 does not limit the scope of this disclosure to any particularimplementation

A TRP configures by high layer a UE with a first UL channel and a secondUL channel for beam recovery request transmission in step 1410. A TRPconfigures by high layer a UE with a first time window length and afirst maximal number transmission number, M_(max,1), for the beamrecovery transmission on a first UL channel in step 1410. A TRPconfigures by high layer a UE with a second time window length and asecond maximal number transmission number, M_(max,2), for the beamrecovery transmission on a first UL channel in step 1410. The UE can berequested to monitor beam failure detection RS to determine if the beamfailure trigger condition is met.

The example for beam failure detection RS can be NR-SS signal in one ormore NR-SS blocks, the NR-PBCH and DMRS in one or more NR-SS blocks, andthe CSI-RS transmission for beam management. The UE detects beam failureevent in step 1420. For the detected beam failure event, the UE firstsends beam recovery request message in a first UL channel in step 1430that is configured by the TRP in step 1410. After sending beam recoveryrequest message in a first UL channel, the UE monitors beam recoveryresponse from the NW during a first time window. If there is no beamrecovery response, the UE can re-send the beam recovery request messagein a first UL channel in step 1430.

When there is no beam recovery response when the number of beam recoveryrequest transmission on a first UL channel achieves M_(max,1) in step1440, the UE sends beam recovery request on a second UL channel in step1450. After sending beam recovery request, the UE monitors beam recoveryresponse during a second time window. If no beam recovery response isreceived within a second time window after sending a beam recoveryrequest on a second UL channel, the UE re-sends the beam recoveryrequest on a second UL channel until the number of beam recovery requesttransmission on a second UL channel achieves M_(max,2) or beam recoveryresponse is received by the UE in step 1450.

When there is beam recovery response corresponding to the beam recoveryrequest sent on first UL channel in step 1440, the UE can process thebeam recovery response and operate the configured action in step 1460.

In some embodiments, when downlink beam failure is determined by a UE,there can be two different cases for TRP Rx beam and UE Tx beam used forUL transmission. One scenario can be the TRP Rx beam and UE Tx beamselected for UL transmission are still aligned. In that scenario, thebeam recovery request can be received successfully by the TRP through aUL channel without beam sweeping operation. Another scenario can be theTRP Rx beam and UE Tx beam selected for UL transmission are misalignedtoo. In that scenario, the beam recovery request sent on a UL channelwithout beam sweeping operation could be lost with high probability dueto the misaligned TRP Rx beam and UE Tx beam.

To ensure the reliability of beam recovery request in that scenario, theUE can be requested to transmit beam recovery request on a UL channelwith beam sweeping operation. When downlink beam failure is determine bya UE, the UE cannot know if the beams selected for UL transmission arestill aligned or not. A UL channel with beam sweeping operation needsmuch more time resource than a UL channel without beam sweepingoperation. The embodiments in the present disclosure provide a way toachieve better tradeoff between time resource overhead and beam recoveryrequest transmission efficiency.

In one embodiment, a UE can be configured with a first UL channel and asecond UL channel for beam recovery request transmission. A TRPconfigures by high layer a UE with a first time window length and afirst timer, T_(max,1), for the beam recovery transmission on a first ULchannel. A TRP configures by high layer a UE with a second time windowlength and a second timer, T_(max,2), for the beam recovery transmissionon a first UL channel. The UE can be requested to monitor beam failuredetection RS to determine if the beam failure trigger condition is met.

The example for beam failure detection RS can be NR-SS signal in one ormore NR-SS blocks, the NR-PBCH and DMRS in one or more NR-SS blocks, andthe CSI-RS transmission for beam management. The UE detects beam failureevent. For the detected beam failure event, the UE first sends beamrecovery request message in a first UL channel. After sending beamrecovery request message in a first UL channel, the UE monitors beamrecovery response from the NW during a first time window. If there is nobeam recovery response, the UE can re-send the beam recovery requestmessage in a first UL channel.

When there is no beam recovery response when the number of beam recoveryrequest transmission on a first UL channel achieves T_(max,1), the UEsends beam recovery request on a second UL channel. After sending beamrecovery request, the UE monitors beam recovery response during a secondtime window. If no beam recovery response is received within a secondtime window after sending a beam recovery request on a second ULchannel, the UE re-sends the beam recovery request on a second ULchannel until the number of beam recovery request transmission on asecond UL channel achieves τ_(max,2) or beam recovery response isreceived by the UE. When there is beam recovery response correspondingto the beam recovery request sent on the first UL channel, the UE canprocess the beam recovery response and operate the configured action.

In one embodiment, a TRP configures by high layer a UE with a first ULchannel and a second UL channel for beam recovery request transmission.A TRP configures by high layer a UE with a first time window length anda first maximal number transmission number, M_(max,1), and a first timerT_(max,1) for the beam recovery transmission on a first UL channel. ATRP configures by high layer a UE with a second time window length and asecond maximal number transmission number, M_(max,2), and a second timerT_(max,2) for the beam recovery transmission on a first UL channel. TheUE can be requested to monitor beam failure detection RS to determine ifthe beam failure trigger condition is met. The example for beam failuredetection RS can be NR-SS signal in one or more NR-SS blocks, theNR-PBCH and DMRS in one or more NR-SS blocks, and the CSI-RStransmission for beam management. The UE detects beam failure event.

For the detected beam failure event, the UE first sends beam recoveryrequest message in a first UL channel. After sending beam recoveryrequest message in a first UL channel, the UE monitors beam recoveryresponse from the NW during a first time window. If there is no beamrecovery response, the UE can re-send the beam recovery request messagein a first UL channel. When there is no beam recovery response when thenumber of beam recovery request transmission on a first UL channelachieves M_(max,1) or a first timer T_(max,1) expires, the UE sends beamrecovery request on a second UL channel.

After sending beam recovery request, the UE monitors beam recoveryresponse during a second time window. If no beam recovery response isreceived within a second time window after sending a beam recoveryrequest on a second UL channel, the UE re-sends the beam recoveryrequest on a second UL channel until the number of beam recovery requesttransmission on a second UL channel achieves M_(max,2) or a second timerT_(max,2) expires or beam recovery response is received by the UE. Whenthere is beam recovery response corresponding to the beam recoveryrequest sent on the first UL channel, the UE can process the beamrecovery response and operate the configured action.

In one embodiment, a first UL channel for beam recovery requesttransmission can be a periodic PUCCH channel. In one example, a specialbit value, for example, all 1s (or all 0s) in the PUCCH payload bit, canbe used to indicate that a beam failure event is detected. Other bitvalues can be used to indicate UL scheduling request, HARQ feedback, CSIreport or beam state information report.

In one embodiment, a second UL channel for beam recovery requesttransmission can be the PRACH channel and a subset of preamble sequencesis configured for beam recovery request through system informationmessage or high layer signaling (e.g., RRC message). When a UEdetermines a beam failure event, the UE can select one preamble sequencefrom the subset of preamble sequence configured for beam recoveryrequest. When the TRP detects preamble sequence for beam recoveryrequest, the TRP sends a beam recovery response that can contain the oneor more of the following information components.

In one example, the beam recovery response can contain the sequence IDof the detected preamble sequence for beam recovery request. In anotherexample, the beam recovery response can contain a UL transmissionscheduling information. In yet another example, the beam recoveryresponse can contain information of a Tx beam that is going to be usedfor the control channel transmission to the UE who reports the detectedpreamble sequence. In such example, it can be a NR-SS block index. Itcan be a CSI-RS resource index or CSI-RS resource index/CSI-RS antennaport index. It can be an Rx beam set ID. In yet another example, thebeam recovery response can contain triggering the transmission of CSI-RStransmission for beam management. In such example, the CSI-RStransmission can be aperiodic transmission with sub-time in a CSI-RSresource to allow the UE to refine Rx beams. The CSI-RS transmission canbe aperiodic transmission to allow the UE to refine TRP Tx beams. TheCSI-RS transmission can be semi-persistent transmission.

A UE can be configured with two UL channels for beam failure recoveryrequest transmission, i.e., a first UL channel and a second UL channel.In one method, when the beam failure recovery request is triggered, theUE can be request to transmit the beam failure recovery request on theearliest available UL channel instance, no matter it is a first ULchannel or a second UL channel. In one method, the UE can be configuredto transmit on both UL channels and then wait for the beam recoveryrequest response for each of the beam recovery request transmission onboth UL channels. Once the UE receives the beam recovery requestresponse from the TRP for one beam recovery request transmission on oneof the UL channels the UE can abort monitoring the responsecorresponding to the other UL channel.

In one embodiment, the UL channel for transmitting beam failure recoveryrequest has multiple time-frequency resource unit. Each time-frequencyresource unit is associated with one SS-block or one CSI-RS resource orone set of CSI-RS antenna ports of CSI-RS resource. A UE can beconfigured with one sequence. The UE can be requested to transmit theUE's configured sequence on one time-frequency resource unit in the ULchannel for transmitting beam failure recovery request. Aftertransmitting the configured sequence, the UE can be requested to monitorthe downlink PDCCH by assuming the DMRS in PDCCH is spatial QCLed withthe SS-block, CSI-RS resource or CSI-RS antenna ports associated withthat time-frequency resource unit where the UE transmit the configuredsequence.

In one embodiment, a set of sequences associated with SS-blocks, CSI-RSresources or sets of CSI-RS antenna ports can be configured to a UE.Each sequence in that set is associated with one SS-block, one CSI-RSresource or one set of CSI-RS antenna ports. The UE can be requested tosend one of those sequences on the UL channel for beam failure recoveryrequest. After sending the sequence, the UE can be requested to monitordownlink PDCCH by assuming the DMRS in PDCCH is spatial QCLed with theSS block, CSI-RS resource or CSI-RS antenna ports associated with thesequence that the UE transmitted.

In one embodiment, a UE can be requested to transmit some beam recoveryrequest message on PUCCH channel when only a subset of but not all ofthe configured BPLs for PDCCH is detected beam failure.

In one embodiment, a UE can send a flag information in PUCCH to indicatethe TRP that a subset of configured BPLs for PDCCH has been detected asbeam failure. After sending the flag information, the UE can assume tomonitor the downlink PDCCH for uplink scheduling and then the UE canreport the index or indices of PDCCH BPLs that have been detected beamfailure to the TRP. In one example, the UE can report which of thoseconfigured BPLs are detected beam failure in MAC-CE signaling. In oneexample the UE can report on bitmap and each bit in the bitmapcorresponds to one of the configured BPL for PUCCH. The value of one bitin the bit map indicates whether beam failure is detected for thecorresponding BPL or not. In one example, the value of one bit being 1can indicate that beam failure is detected for the BPL corresponding tothat bit. After reporting the failed BPL, the UE can assume to stopmonitoring the failed BPL for PDCCH.

In one embodiment, a UE can send flag information and the indexinformation of BPLs that are detected beam failure in PUCCH. In oneexample, the UE can report one bitmap and each bit in the bitmapcorresponds to one of the configured BPL for PUCCH. The value of one bitin the bit map indicates whether beam failure is detected for thecorresponding BPL or not. In one example, the value of one bit being 1can indicate that beam failure is detected for the BPL corresponding tothat bit.

In some embodiments, the UE can be configured to indicate one of thefollowings is transmitted in one reporting instance and also transmitthe indicated reporting case. In one example, a normal beam reporting istransmitted. In such example, the UE can report one or more beam ID (forexample, SSB Index or index of CSI-RS resource) and the associatedL1-RSRP and differential L1-RSRP measurement of reported SSB index orCSI-RS resource index.

In another example, a reporting the failure of a subset of PDCCH beamsis transmitted. In such example, the UE can report one bitmap and eachbit in the bitmap corresponds to one of the configured Tx beam forPDCCH. The value of one bit can indicate whether the corresponding beamis failed or not. In one instance, each bit in the bitmap can beassociated with one TCI state configured to PDCCH for one UE for thespatial QCL configuration. In one instance, 4 TCI states {M1, M2, M3,M4} are configured for one UE for the spatial QCL configuration for UEto receive the PDCCH. A 4-bit bitmap {b0, b1, b2, b3} can be used toindicate the failure status of beam link of the DL RS associated withTCI states {M1, M2, M3, M4}. The UE can assume the bit b0 is used toindicate for TCI state with lowest TCI index among {M1, M2, M3, M4} andcan assume bit b1 is used to indicate for TCI state with the secondlowest TCI index among {M1, M2, M3, M4}, and can assume bit b2 is usedto indicate for TCI state with the third lowest TCI index among {M1, M2,M3, M4} can assume bit b3 is used to indicate for TCI state with thelargest TCI index among {M1, M2, M3, M4}. In another instance, the UEcan also report one or more newly identified beams and/or theirassociated L1-RSRP measurement. In yet another instance, the UE can alsoreport one or more selected Tx beam IDs and/or their associated L1-RSRPmeasurement. In yet another instance, for periodic beam reporting, ifthe UE is configured to select and report N Tx beams and their L1-RSRPmeasurement. In this instance, the UE can be requested to report N−1 Txbeams and their associated L1-RSRP.

In one embodiment, the beam failure recovery request is transmitted. TheUE can report the index of one Tx beam (for example, one SSB index orCSI-RS resource index) and/or the associated L1-RSRP measurement. Insuch embodiment, if the UE is configured to select/report N Tx beams andtheir L1-RSRP measurement. In this mode, the UE can also be requested toreport N−1 Tx beams and their associated L1-RSRP.

In one embodiment, a combination of normal beam reporting and reportingthe failure of a subset of PDCCH beams is transmitted. When the triggercondition for reporting failure of a subset of PDCCH beam is met, the UEcan be requested to report the information of those failed PDCCH beamsand N-L Tx beams selected according to the configuration of normal beammeasurement and reporting, where L can be 1, 2, . . . , N, where N isthe number of Tx beams the UE is configured to report in one beamreporting instance.

In one embodiment, a combination of normal beam reporting and the beamfailure recovery request are transmitted. When the trigger condition forreporting beam failure recovery request is met, the UE can be requestedto report the beam failure recovery request message and N-L Tx beamsselected according to the configuration of normal beam measurement andreporting, where L can be 1, 2, . . . , N, where N is the number of Txbeams the UE is configured to report in one beam reporting instance. Thebeam failure recovery request can include one or more of the following:(1) one flag to indicate that is a beam failure recovery request; (2)the index of one CSI-RS resource or SSB as the newly identified beamthat will be used by the NW to transmit response to that beam failurerecovery request; and (3) The L1-RSRP (or RSRQ, or SINR) associated withthe reported CSI-RS or SSB index.

In one embodiment, a UE is requested to report the CRIs/SSBIs and theL1-RSRP and differential L1-RSRP of reported CRIs/SSBIs in periodic CSIreporting. When the Tx beam(s) of a subset of downlink control channelsare declared failure, the UE can do one of the following.

In one example, the UE can report a special value of one L1-RSRP ordifferential L1-RSRP to indicate the reported CRI/SSBI corresponding tothat L1-RSRP or differential L1-RSRP is a failed beam. Some example ofthe special value can be all 1s or all 0s.

In another example, the UE can be report a special value of one L1-RSRPor differential L1-RSRP to indicate the reported CRI/SSBI correspondingto that L1-RSRP or differential L1-RSRP is used to report the beamfailure state of downlink control channel. In this case, the bits ofthat CRI/SSBI can be used indicate which ones of the CORESETs has failedbeam. In one example, the bits of that CRI/SSBI can be used as a bitmapto indicate which ones of the CORESETs of that UE has failed beam. Inone example, 6 bits {b₁b₂b₃b₄b₅b₆} are used for CRI/SSBI and each bit inb₁b₂b₃b₄b₅b₆ can be used to indicate the beam failure status of oneCORESET configured to that UE. The value of each bit being 1 canindicate the associated CORESET has beam failure and the value of eachbit being 0 can indicate the associated CORESET has no beam failure. Bitb₁ can be associated with the CORESET with lowest CORESET-ID among theCORESETs configured to that UE. Bit b₂ can be associated with theCORESET with second lowest CORESET-ID among the CORESETs configured tothat UE. Bit b₃ can be associated with the CORESET with third lowestCORESET-ID among the CORESETs configured to that UE, so on so forth.

In one embodiment, the UE reports 2-bit in one reporting instance toindicate the type of reporting content in one reporting instance. In oneexample, the value of 2-bit being 00 can indicate the reporting contentin one reporting instance is normal beam reporting as described above;the value of 2-bit being 01 can indicate the reporting content in onereporting instance is reporting the failure of a subset of PDCCH beams.The UE can be requested to report up to B bits payload, {b₀, b₁, . . . ,b_(B-1)}, in one beam reporting instance.

The UE can be requested to use first two bits b₀, b₁ to indicate whichcontent is reported in this beam reporting instance through the rest ofbits in up to B bits payload. In one example, if the UE reports normalbeam reporting, the UE can set the value of b₀, b₁ to be 00 and usessome or all of the rest bits to report one or more SSB indices orindices of CSI-RS resources and their associated L1-RSRP anddifferential L1-RSRP; If the UE reports the failure of a subset of PDCCHbeams, the UE can set the value of b₀, b₁ to be 01 and then uses bitsb₂, b₃, . . . , b_(Q+1) as bitmap to indicate the failure status of eachPDCCH beam of Q configured PDCCH beams; If the UE reports the beamfailure recovery request, the UE can set the value of b₀, b₁ to 10 andthen some bits in {b₂, b₃, . . . , b_(B-1)} to report one index ofselected SSB or CSI-RS resource and/or the UE's associated L1-RSRPmeasurement.

In one embodiment, the UE can reports 1-bit in one reporting instance toindicate the type of reporting content in one reporting instance. In oneexample, the value of 1-bit being 0 can indicate the reporting contentin one reporting instance is normal beam reporting as described above;the value of 1-bit being 1 can indicate the reporting content in onereporting instance is beam failure request and the UE can report oneselected SSB index or index of CSI-RS resource and/or the UE'sassociated L1-RSRP measurement.

The UE can be requested to report up to B bits payload, {b₀, b₁, . . . ,b_(B-1)}, in one beam reporting instance. The UE can be requested to usefirst one bit b₀ to indicate which content is reported in this beamreporting instance through the rest of bits in up to B bits payload. Inone example, if the UE reports normal beam reporting, the UE can set thevalue of b₀ to be 0 and uses some or all of the rest bits to report oneor more SSB indices or indices of CSI-RS resources and their associatedL1-RSRP and differential L1-RSRP; If the UE reports the beam failurerecovery request, the UE can set the value of b₀ to 1 and then some bitsin {b₁, b₂, . . . , b_(B-1)} to report one index of selected SSB orCSI-RS resource and/or the UE's associated L1-RSRP measurement.

In one embodiment, the UE can dynamically determine the reportingcontent selection based on the number of configured PDCCH beams. If onlyone Tx beam is configured for the UE to monitor for the failure ofPDCCH, the UE can determine that the UE reports normal beam reporting orbeam failure recovery request. Then only 1 bit in the reporting contentcan be used to indicate which content is contained in one beam reportinginstance. If more than one Tx beams are configured for the UE to monitorfor the failure of PDCCH, the UE can determine that the UE can reportnormal beam reporting, failure of a subset of PDCCH beams or beamfailure recovery request; then two bits in the reporting content can beused to indicate which content is contained in one beam reportinginstance.

In one embodiment, the UE can be requested to apply different scramblesequences on the reporting bits {b₀, b₁, . . . , b_(B-1)} for differentreporting contents. In one example, the UE can be requested to a firstscramble sequence on the reporting bits {b₀, b₁, . . . , b_(B-1)} if theUE reports normal beam reporting in one reporting instance. In oneexample, the UE can be requested to a second scramble sequence on thereporting bits {b₀, b₁, . . . , b_(B-1)} if the UE reports the failureof a subset of PDCCH beams in one reporting instance. In one example,the UE can be requested to a third scramble sequence on the reportingbits {b₀, b₁, . . . , b_(B-1)} if the UE reports beam failure recoveryrequest in one reporting instance.

In some embodiments, if the UE is configured with both SSB and CSI-RSfor new beam identification, the UE can be requested to only report oneCSI-RS resource index as the new beam when reporting beam failurerecovery request in PUCCH channel.

In some embodiments, if the UE is configured with both SSB and CSI-RSfor new beam identification, the UE can be requested to add one bitappended to the SSB index bits or CSI-RS resource index bits to indicatewhether one reported index is SSB index or CSI-RS resource index. Thevalue of that one bit can be used to indicate the type of RS of that thereported DL RS resource in beam failure request sent in PUCCH.

In some embodiments, after the UE sends beam failure request in one beamreporting instance in PUCCH, the UE can be requested to monitor CORESETthat is dedicatedly configured for monitoring beam recovery requestresponse.

In some embodiments, a UE can be configured with one preamble sequenceand/or a set of preamble sequence for the transmission of beam recoveryrequest. The UE can be requested to calculate the scheme to receive thebeam recovery response according to the configuration of preamblesequence.

In one embodiment, a UE can be configured with one preamble sequence.The UE can be requested to send the configured preamble sequence on someselected time-frequency resource when beam failure is detected thetrigger condition for beam recovery request is satisfied. After sendingthe preamble sequence, the UE can be requested to monitor the PDCCH byassuming the Tx beam corresponding to the CSI-RS resource or SS-blockassociated with the selected time-frequency resource is used to transmitthe PDCCH by the TRP and by assuming that the PDCCH can be scrambled bythe UE ID.

In one embodiment, a UE can be configured with a set of preamblesequences. The UE can be requested to select one from the configuredpreamble sequences and send the selected preamble sequence on someselected time-frequency resource when beam failure is detected thetrigger condition for beam recovery request is satisfied. After sendingthe preamble sequence, the UE can be requested to monitor the PDCCH byassuming the Tx beam corresponding to the CSI-RS resource or SS-blockassociated with the selected time-frequency resource is used to transmitthe PDCCH by the TRP and by assuming that the PDCCH can be scrambled bythe UE ID. After receiving the beam response, the UE can be requested toreport the UE ID in the uplink transmission that is scheduled by beamrecovery response.

In one embodiment, a UE can be configured with one preamble sequence aand a set of preamble sequences. The UE can be requested to send theconfigured preamble sequence a on some selected time-frequency resourcewhen beam failure is detected the trigger condition for beam recoveryrequest is satisfied. After sending the preamble sequence, the UE can berequested to monitor the PDCCH by assuming the Tx beam corresponding tothe CSI-RS resource or SS-block associated with the selectedtime-frequency resource is used to transmit the PDCCH by the TRP and byassuming that the PDCCH can be scrambled by the UE ID.

If the UE does not receive response within a configured timer, the UEcan re-send preamble sequence a on some selected time-frequencyresource. If the number of transmitting preamble sequence a withoutsuccessful response achieves some configured threshold or a timer fortrying sending preamble sequence a expires, the UE can be requested touse the configured set of preamble sequences for beam recovery requesttransmission. The UE can be requested to select one from the configuredpreamble sequences and send the selected preamble sequence on someselected time-frequency resource when beam failure is detected thetrigger condition for beam recovery request is satisfied.

After sending the preamble sequence, the UE can be requested to monitorthe PDCCH by assuming the Tx beam corresponding to the CSI-RS resourceor SS-block associated with the selected time-frequency resource is usedto transmit the PDCCH by the TRP and by assuming that the PDCCH can bescrambled by the UE ID. After receiving the beam response, the UE can berequested to report the UE ID in the uplink transmission that isscheduled by beam recovery response.

The present disclosure relates generally to wireless communicationsystems and, more specifically, to vehicular communication networkprotocols, including vehicle-to-device, vehicle-to-vehicle, andvehicle-to-network communication resource allocation and synchronizationmethods. A communication system includes a downlink (DL) that conveyssignals from transmission points such as base stations (BSs) or NodeBsto user equipments (UEs) and an uplink (UL) that conveys signals fromUEs to reception points such as NodeBs. Additionally a sidelink (SL) mayconvey signals from UEs to other UEs or other non-infrastructure basednodes. A UE, also commonly referred to as a terminal or a mobilestation, may be fixed or mobile and may be a cellular phone, a personalcomputer device, etc. A NodeB, which is generally a fixed station, mayalso be referred to as an access point or other equivalent terminologysuch as eNodeB. The access network including the NodeB as related to3GPP LTE is called as Evolved Universal Terrestrial Access Network(E-UTRAN).

In a communication system, DL signals can include data signals conveyinginformation content, control signals conveying DL control information(DCI), and reference signals (RS) that are also known as pilot signals.A NodeB transmits data information through a physical DL shared channel(PDSCH). A NodeB transmits DCI through a physical DL control channel(PDCCH) or an enhanced PDCCH (EPDCCH).

Messages are transmitted on the PDCCH using a cell radio networktemporary identifier (C-RNTI) to identify the intended UE. The C-RNTI isthe RNTI to be used by a given UE while the UE is in a particular cellafter the UE and a NodeB establish an RRC connection. A NodeB transmitsone or more of multiple types of RS including a UE-common RS (CRS), achannel state information RS (CSI-RS), or a demodulation RS (DMRS). ACRS is transmitted over a DL system bandwidth (BW) and can be used byUEs to obtain a channel estimate to demodulate data or controlinformation or to perform measurements.

To reduce CRS overhead, a NodeB may transmit a CSI-RS with a smallerdensity in the time and/or frequency domain than a CRS. DMRS can betransmitted only in the BW of a respective PDSCH or EPDCCH and a UE canuse the DMRS to demodulate data or control information in a PDSCH or anEPDCCH, respectively. A transmission time interval for DL channels isreferred to as a sub-frame (SF) and can have, for example, duration of 1millisecond. A number of ten SFs is referred to as a frame and isidentified by a system frame number (SFN).

Traditionally, cellular communication networks have been designed toestablish wireless communication links between mobile devices (UEs) andfixed communication infrastructure components (such as base stations oraccess points) that serve UEs in a wide or local geographic range.However, a wireless network can also be implemented by utilizing onlydevice-to-device (D2D) communication links without the need for fixedinfrastructure components. This type of network is typically referred toas an “ad-hoc” network.

A hybrid communication network can support devices that connect both tofixed infrastructure components and to other D2D-enabled devices. WhileUEs such as smartphones can be envisioned for D2D networks, vehicularcommunication can also be supported by a communication protocol wherevehicles exchange control or data information with other vehicles orother infrastructure or UEs. Such a network is referred to as a V2Xnetwork. Multiple types of communication links can be supported by nodessupporting V2X in the network and can utilize same or differentprotocols and systems.

FIG. 15 illustrates an example use case of a vehicle-centriccommunication network 1500 according to embodiments of the presentdisclosure. The embodiment of the use case of a vehicle-centriccommunication network 1500 illustrated in FIG. 15 is for illustrationonly. FIG. 15 does not limit the scope of this disclosure to anyparticular implementation.

The vehicular communication, referred to as Vehicle-to-Everything (V2X),contains the following three different types: vehicle-to-vehicle (V2V)communications; vehicle-to-infrastructure (V2I) communications; andvehicle-to-pedestrian (V2P) communications.

These three types of V2X can use “co-operative awareness” to providemore intelligent services for end-users. This means that transportentities, such as vehicles, roadside infrastructure, and pedestrians,can collect knowledge of their local environment (e.g., informationreceived from other vehicles or sensor equipment in proximity) toprocess and share that knowledge in order to provide more intelligentservices, such as cooperative collision warning or autonomous driving.

A V2X communication can be used to implement several types of servicesthat are complementary to a primary communication network or to providenew services based on a flexibility of a network topology. V2X cansupport unicasting, broadcasting, or group/multicasting as potentialmeans for V2V communication 100 where vehicles are able to transmitmessages to all in-range V2V-enabled devices or to a subset of devicesthat are members of particular group. The protocol can be based onLTE-D2D or on a specialized LTE-V2V protocol.

V2X can support V2I communication 1501 between one or more vehicles andan infrastructure node to provide cellular connectivity as well asspecialized services related to control and safety of vehicular traffic.V2P communication 1502 can also be supported, for example to providesafety services for pedestrians or traffic management services. V2Xmulticast communication 1503 can be used to provide safety and controlmessages to large numbers of vehicles in a spectrally efficient manner.

The two primary standardized messages for V2V/V2I communication are theperiodic beacons called cooperative awareness messages (CAM) and theevent-triggered warning messages, called decentralized environmentnotification messages (DENM). The CAMs are periodically broadcastedbeacons used to maintain awareness of the surrounding vehicles. Thesemessages are sent with an adaptive frequency of 1-10 Hz. The CAMsinclude information such as position, type and direction. The DENMs areevent-triggered warning messages which are generated to alertneighboring vehicles about potential hazards.

While vehicle devices can be able to support many differentcommunication protocols and include support of mandatory or optionalfeatures, since the traffic types, QoS requirements, and deploymenttopologies are distinct from other types of communications, thehardware/software on a vehicle for supporting V2X can have a reduced orspecialized functionality compared to other devices. For example,protocols related to low-complexity, low-data rate, and/or low-latencyfor machine-type communications 1504 can be supported such as, forexample, traffic tracking beacons. Satellite-based communication 1505can also be supported for V2X networks for communication or positioningservices.

A direct communication between vehicles in V2V is based on a sidelink(SL) interface. Sidelink is the UE to UE interface for SL communicationand SL discovery. The SL corresponds to the PC5 interface as defined inREF 6. SL communication is defined as a functionality enabling proximityservices (ProSe) Direct Communication as defined in LTE specificationbetween two or more nearby UEs using E-UTRA technology but nottraversing any network node.

E-UTRAN allows such UEs that are in proximity of each other to exchangeV2V-related information using E-UTRA(N) when permission, authorizationand proximity criteria are fulfilled. The proximity criteria can beconfigured by the MNO. However, UEs supporting V2V Service can exchangesuch information when served by or not served by E-UTRAN which supportsV2X Service. The UE supporting V2V applications transmits applicationlayer information (e.g. about the UE's location, dynamics, andattributes as part of the V2V Service). The V2V payload must be flexiblein order to accommodate different information contents, and theinformation can be transmitted periodically according to a configurationprovided by the MNO.

V2V is predominantly broadcast-based; V2V includes the exchange ofV2V-related application information between distinct UEs directlyand/or, due to the limited direct communication range of V2V, theexchange of V2V-related application information between distinct UEs viainfrastructure supporting V2X Service, e.g., RSU, application server,etc.

FIG. 16 illustrates an example SL interface 1600 according toembodiments of the present disclosure. The embodiment of the SLinterface 1600 illustrated in FIG. 16 is for illustration only. FIG. 16does not limit the scope of this disclosure to any particularimplementation

As shown in FIG. 16, FIG. 16 illustrates an example SL interfaceaccording to illustrative embodiments of the present disclosure. WhileUL designates the link from UE 1601 to NodeB 1603 and DL designates thereverse direction, SL designates the radio links over the PC5 interfacesbetween UE 1601 and UEs 1602. The UE 1601 transmits a V2V message tomultiple UEs 1602 in the SL. SL communication happens directly withoutusing E-UTRAN technology and not traversing any network node NodeB 1603.The PC5 interface re-uses existing frequency allocation, regardless ofthe duplex mode (frequency division duplex (FDD) or time division duplex(TDD).

To minimize hardware impact on a UE and especially on the poweramplifier of the UE, transmission of V2V links occurs in the UL band incase of FDD. Similar, the PC5 interface uses SFs that are reserved forUL transmission in TDD. The signal transmission is based on singlecarrier frequency division multiple access (SC-FDMA) that is also usedfor UL transmission. The new channels can be largely based on thechannel structure applicable for the transmission of the physical ULshared channel (PUSCH).

An SL transmission and reception occurs with resources assigned to agroup of devices. A resource pool (RP) is a set of resources assignedfor sidelink operation. It consists of the subframes and the resourceblocks within the subframe. For SL communication, two additionalphysical channels are introduced: physical sidelink control channel(PSCCH) carrying the control information, and physical sidelink sharedchannel (PSSCH) carrying the data.

FIG. 17 illustrates an example resource pool for PSCCH 1700 according toembodiments of the present disclosure. The embodiment of the resourcepool for PSCCH 1700 illustrated in FIG. 17 is for illustration only.FIG. 17 does not limit the scope of this disclosure to any particularimplementation

FIG. 17 illustrates an example resource pool for PSCCH according toillustrative embodiments of the present disclosure. In one example, thepool is defined in frequency (by parameter), for example, PRBnum thatdefines the frequency range in physical resource block (PRB) bandwidthunits; and PRBstart and PRBend define the location in the frequencydomain within the uplink band. In another example, the pool is definedin the time domain (by a bitmap) that indicates the 1 msec sub-framesused for PSCCH transmission.

This block of resources is repeated with a period defined by a parameterSC-Period (expressed in sub-frame duration, i.e. 1 msec). The range ofpossible values for SC-Period is from 40 msec to 320 msec: low valuesare supported for voice transmission.

All the parameters needed to define the resource pool are broadcasted ina system information block (SIB) by the network. The devices which arenot within coverage (and hence cannot acquire the SIB) may use somepre-configured values internally stored. The PSCCH is used by the V2Xtransmitting UE to make the members of the V2X transmitting UE's groupaware of the next data transmission that may occur on the PSSCH. The V2Xtransmitting UE sends the sidelink control information (SCI) format 1 onthe PSCCH as shown in TABLE 1.

TABLE 1 The sidelink control information Parameter Usage and NotesPriority 3 bits Resource reservation 4 bits Frequency resource locationof give the receiving devices information initial transmission and aboutthe resources of the PSSCH that retransmission may be decoded in thefrequency domain Time gap between initial 4 bits transmission andretransmission Modulation and coding scheme 5 bits Retransmission index1 bit to indicate first or second transmission Reserved information bitsTo make the size of SCI format 1 to be 32 bits

Devices interested in receiving V2X services blindly scan the wholePSCCH pool to search if a SCI format matching their group identifier canbe detected. On the transmitting device side, resources to transmit theSCI format information may be selected within the PSCCH pool.

There are two types of resource pools: reception resource pools (Rx RPs)and transmission resource pools (Tx RPs). These are either signaled bythe NodeB for in-coverage case or a pre-configured value is used for theout-of-coverage case. Within a cell, there may be more Rx RPs than TxRPs to enable reception from adjacent cells or from out-of-coverage UEs.Two modes of resource allocation have been defined for SL communication:mode 3 (e.g., scheduled resource allocation) and mode 4 (UE autonomousresource selection).

In mode 3, transmission of V2X on sidelink is scheduled by NodeB. The UEreceives DCI format 5A from the NodeB a and then sends SCI format overthe resources indicated by DCI format 5A that is illustrated in TABLE 2.Access to the sidelink resources is driven by the NodeB. The UE needs tobe connected to transmit data.

TABLE 2 SCI format Parameter Usage and Notes Carrier indicator Carrierindicator to support cross carrier scheduling Lowest index of thesubchannel The resource allocation for PSCCH on allocation to theinitial V2X sidelink transmission SCI format 1 fields The resourceallocation for PSCH SL index 2 bits SL SPS configuration index 3 bitsConfigure the SPS transmission on sidelink Activation/release indication1 bits to activate or release the SPS transmission on sidelink

In the present disclosure, schemes of transmit diversity transmissionfor V2V/V2X are proposed. Specially, the methods of transmissionschemes, DMRS design and SCI/DCI format design are provided in thepresent disclosure.

In one embodiment, the UE can be configured to detect DMRS with twoantenna ports. This design is useful to the V2V/V2X UE to supporttransmit diversity with two antenna ports, for example SFBC, STBC andlarge delay CDD. In addition to support two antenna ports, the design ofnew DMRS may enable the rel14 to measure the PSSCH-RSRP based on the oneof the antenna port in the newly designed DMRS.

In one embodiment, the DMRS of those two antenna ports for PSSCH P₀, P₁are mapped to different DMRS OFDM symbols. In one method, the DMRS ofantenna port P₀ are mapped to OFDM symbols 2 and 8 (1810 and 1812) andthe DMRS of antenna port P₁ are mapped to OFDM symbols 5 and 11 (1811and 1813). In one method, the DMRS of antenna port P₀ are mapped to OFDMsymbols 2 and 5 (1810 and 1811) and the DMRS of antenna port P₁ aremapped to OFDM symbols 8 and 11 (1812 and 1813).

FIG. 18 illustrates an example DMRS configuration 1800 according toembodiments of the present disclosure. The embodiment of the DMRSconfiguration 1800 illustrated in FIG. 18 is for illustration only. FIG.18 does not limit the scope of this disclosure to any particularimplementation. And the same reference signal sequence can be used forDMRS antenna ports P₀ and P₁ as shown in TABLE 3.

TABLE 3 Reference signal sequence PSSCH Sidelink transmission modes 3and 4 Group enabled hopping n_(ID) ^(RS) n_(ID) ^(X) n_(s) 2n_(ss)^(PSSCH) first DM-RS symbol in a slot 2n_(ss) ^(PSSCH) +1 second DM-RSsymbol in a slot f_(ss) └n_(ID) ^(X)/16┘mod30 Sequence disabled hoppingCyclic shift n_(cs, λ) └n_(ID) ^(X)/2┘mod8 Orthogonal └w^(λ) (·)┘ [+1 +1+1 +1] if n_(ID) ^(X) mod2 = 0 sequence [+1 −1 +1 −1] if n_(ID) ^(X)mod2 = 1 Reference M_(sc) ^(RS) M_(sc) ^(PSSCH) signal length

In some embodiments, different reference signal sequences can be usedfor two DMRS antenna ports P₀ and P₁. In one example, the referencesignal for DMRS antenna ports P₀ and P₁ are mapped to OFDM symbols {2,5, 8, 11} and the reference signal for DMRS can be generated accordingone or more of the fields in following TABLE 4A.

TABLE 4A Reference signal for DMRS PSSCH Sidelink transmission modes 3and 4 Group enabled hopping n_(ID) ^(RS) n_(ID) ^(X) n_(s) 2n_(ss)^(PSSCH) first DM-RS symbol in a slot 2n_(ss) ^(PSSCH) +1 second DM-RSsymbol in a slot f_(ss) └n_(ID) ^(X)/16┘mod30 Sequence disabled hoppingCyclic n_(cs, λ) └n_(ID) ^(X)/2┘mod 8 for antenna port P₀ (└n_(ID)^(X)/2┘ + 4)mod8 for antenna port shift P₁ Orthogonal └w^(λ) (·)┘ [+ 1+1 +1 +1] if n_(ID) ^(X) mod2 = 0 [+1 +1 −1 −1] if n_(ID) ^(X) mod 2 = 0sequence [+ 1 −1 +1 −1] if n_(ID) ^(X) mod2 = l [+1 −1 −1 +1] if n_(ID)^(X) mod 2 = 1 for antenna port P₀ for antenna port P₁ or [+1 −1 −1 +1]if n_(ID) ^(X) mod 2 = 0 [+1 +1 −1 −1] if n_(ID) ^(X) mod 2 = 1 forantenna port P₁ Reference M_(sc) ^(RS) M_(sc) ^(PSSCH) signal lengthNumber of υ 2 layers Number of P 2 antenna ports

The DMRS antenna ports using two different reference signal sequencescan be mapped to the same OFDM symbols. In one example, DMRS antennaports P₀ and P₁ are mapped to DMRS symbols 2/5/8/11.

In one embodiment, fours sequence, sequence 0, sequence 1, sequence 2and sequence 3, are generated according to TABLE 4B. Sequence 0 and 2are sequence for first DMRS in a lot and sequence 1 and 3 are sequencesfor second DMRS in a slot. In an example, sequence 0 is mapped tosymbols 2 and 8 for DMRS antenna port P₀, and sequence 1 is mapped tosymbols 5 and 11 for DMRS antenna port P₀. Sequence 2 is mapped tosymbols 2 and 8 for DMRS antenna port P₁, and sequence 3 is mapped tosymbols 5 and 11 for DMRS antenna port P₁. OCC code can be applied foreach antenna port. For antenna port P₀, the OCC code can be:

-   -   [+1 +1 +1 +1] if n_(ID) ^(X) mod 2=0    -   [+1 −1 +1 −1] if n_(ID) ^(X) mod 2=1

For antenna port P₁, the OCC code can be one of the followings:

-   -   [+1 +1 −1 −1] if n_(ID) ^(X) mod 2=0    -   [+1 −1 −1 +1] if n_(ID) ^(X) mod 2=1    -   [+1 +1 −1 −1] if n_(ID) ^(X) mod 2=1    -   [+1 −1 −1 +1] if n_(ID) ^(X) mod 2=0    -   [+1 −1 −1 +1] if n_(ID) ^(X) mod 2=0    -   [+1 +1 −1 −1] if n_(ID) ^(X) mod 2=1    -   [+1 −1 −1 +1] if n_(ID) ^(X) mod 2=1    -   [+1 +1 −1 −1] if n_(ID) ^(X) mod 2=0

TABLE 4B Sequence generation PSSCH Sidelink transmission modes 3 and 4Group enabled hopping n_(ID) ^(RS) n_(ID) ^(X) n_(s) 2n_(ss) ^(PSSCH)first DM-RS symbol in a slot 2n_(ss) ^(PSSCH) + 1 second DM-RS symbol ina slot f_(ss) └n_(ID) ^(X)/16┘mod30 Sequence disabled hopping Cyclicshift n_(cs, λ) └n_(ID) ^(X)/2┘mod8 for sequence 0 (for (└n_(ID)^(X)/2┘ + 4) mod8 for first DMRS symbol in a lot) and sequence 2 (forfirst DMRS sequence 1 (for second DMRS symbol in a lot) and sequence 3symbol in a slot) (for second DMRS symbol in a lot). Reference M_(sc)^(RS) M_(sc) ^(PSSCH) signal length Number of υ 2 layers Number of P 2antenna ports

In one example, the sequence can be mapped for antenna ports P₀ and P₁.In one instance, for antenna port P₀, sequence 0 is mapped to symbols 2and 8, sequence 3 is mapped to symbols 5 and 11. In one instance, forantenna port P₁, sequence 2 is mapped to symbols 2 and 8, sequence 1 ismapped to symbols 5 and 11. In one instance, for antenna port P₀, theOCC code can be one of the followings:

$\begin{matrix}\lbrack {{+ 1}\mspace{20mu} + 1\mspace{20mu} + 1\mspace{20mu} + 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 0} \\\lbrack {{+ 1}\mspace{20mu} - 1\mspace{20mu} + 1\mspace{20mu} - 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 1}\end{matrix}.$

In one instance, for antenna port P₁, the OCC code can be one of thefollowings:

$\quad\begin{matrix}\lbrack {{- 1}\mspace{20mu} + 1\mspace{20mu} - 1\mspace{20mu} + 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 0} \\\lbrack {{- 1}\mspace{20mu} - 1\mspace{20mu} - 1\mspace{20mu} - 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 1}\end{matrix}$

In one example, the sequence can be mapped for antenna ports P₀ and P₁.In one example, for antenna port P₁, sequence 0 is mapped to symbols 2and 8, sequence 3 is mapped to symbols 5 and 11. In one example, forantenna port P₀, sequence 2 is mapped to symbols 2 and 8, sequence 1 ismapped to symbols 5 and 11. In one example, for antenna port P₁, the OCCcode can be one of the followings:

$\begin{matrix}\lbrack {{+ 1}\mspace{20mu} + 1\mspace{20mu} + 1\mspace{20mu} + 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 0} \\\lbrack {{+ 1}\mspace{20mu} - 1\mspace{20mu} + 1\mspace{20mu} - 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 1}\end{matrix}.$

In one example, for antenna port P₀, the OCC code can be one of thefollowings:

$\begin{matrix}\lbrack {{- 1}\mspace{20mu} + 1\mspace{20mu} - 1\mspace{20mu} + 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 0} \\\lbrack {{- 1}\mspace{20mu} - 1\mspace{20mu} - 1\mspace{20mu} - 1} \rbrack & {{{if}\mspace{14mu} n_{ID}^{X}\mspace{11mu} {mod}\mspace{11mu} 2} = 1}\end{matrix}.$

FIG. 19 illustrates another example DMRS configuration 1900 according toembodiments of the present disclosure. The embodiment of the DMRSconfiguration 1900 illustrated in FIG. 19 is for illustration only. FIG.19 does not limit the scope of this disclosure to any particularimplementation

In one embodiment, the DMRS of two antenna ports for PSSCH P₀ and P₁ aremapped to different REs of same DMRS OFDM symbols. The even number ofREs is mapped to a first antenna port and the odd number of REs ismapped to a second antenna port. An example is illustrated in FIG. 19.

In one example, the DMRS reference signal sequences are generatedaccording to TABLE 3. On Symbols {2, 5, 8, 11}, the even number of REs{0, 2, 4, . . . , M_(sc) ^(PSSCH)−2} within the PSSCH allocation aremapped to antenna port P₀ and the odd number of REs {1, 3, 5, . . . ,M_(sc) ^(PSSCH)−1} within the PSSCH allocation are mapped to antennaport P₁.

In one example, in symbols {2, 8}, the even number of REs {0, 2, 4, . .. , M_(sc) ^(PSSCH)−2} within the PSSCH allocation are mapped to antennaport P₀ and the odd number of REs {1, 3, 5, . . . , M_(sc) ^(PSSCH)−1}within the PSSCH allocation are mapped to antenna port P₁. And onsymbols {5, 11}, the even number of REs {0, 2, 4, . . . , M_(sc)^(PSSCH)−2} within the PSSCH allocation are mapped to antenna port P₁and the odd number of REs {1, 3, 5, . . . , M_(sc) ^(PSSCH)−1} withinthe PSSCH allocation are mapped to antenna port P₀.

In one example, in symbols {2, 5}, the even number of REs {0, 2, 4, . .. , M_(sc) ^(PSSCH)−2} within the PSSCH allocation are mapped to antennaport P₀ and the odd number of REs {1, 3, 5, . . . , M_(sc) ^(PSSCH)−1}within the PSSCH allocation are mapped to antenna port P₁. And insymbols {8, 11}, the even number of REs {0, 2, 4, . . . , M_(sc)^(PSSCH)−2} within the PSSCH allocation are mapped to antenna port P₁and the odd number of REs {1, 3, 5, . . . , M_(sc) ^(PSSCH)−1} withinthe PSSCH allocation are mapped to antenna port P₀.

In one example, in symbols {2, 11}, the even number of REs {0, 2, 4, . .. , M_(sc) ^(PSSCH)−2} within the PSSCH allocation are mapped to antennaport P₀ and the odd number of REs {1, 3, 5, . . . , M_(sc) ^(PSSCH)−1}within the PSSCH allocation are mapped to antenna port P₁. And insymbols {5, 8}, the even number of REs {0, 2, 4, . . . , M_(sc)^(PSSCH)−2} within the PSSCH allocation are mapped to antenna port P₁and the odd number of REs {1, 3, 5, . . . , M_(sc) ^(PSSCH)−1} withinthe PSSCH allocation are mapped to antenna port P₀.

In one embodiment, a UE can be configured with DMRS sequences andmapping that can support specific pre-coder cycling scheme. The UE canbe requested to only use the DMRS transmitted on particular timelocation and/or frequency location to estimate the channel fordemodulation of PSSCH transmission on particular time location and/orfrequency location. This embodiment is useful to support pre-codercycling transmission scheme along frequency domain and/or time domain.In pre-coder cycling transmission scheme, the pre-coder can be changedalong frequency and/or time and the UE needs to know which part of DMRScan be used to the estimate the channel for demodulation of oneparticular part of PSSCH. Pre-coder cycling can also be called pre-coderswitching, pre-coder vector switching, pre-coding vector switching andPVS. The term ‘pre-coder cycling’ is exemplary and can be substitutedwith any other names or labels without changing the substances of thisdisclosure.

In one embodiment, the UE can be configured to assume that the samepre-coder(s) are applied to DMRS symbols and data symbols in PSSCH asfollows as showed in FIG. 18. In one example, the same pre-coder(s) areapplied to DMRS symbol 2, 1810 and data symbols {0, 1, 3} in PSSCH inone subframe. In one example, the same pre-coder(s) are applied to DMRSsymbol 5, 1811 and data symbols {4, 6} in PSSCH in one subframe. In oneexample, the same pre-coder(s) are applied to DMRS symbol 8, 1812 anddata symbols {7, 9} in PSSCH in one subframe. In one example, the samepre-coder(s) are applied to DMRS symbol 11, 1813 and data symbols {10,12} in PSSCH in one subframe.

In one embodiment, the UE can be configured to assume same pre-coder(s)are applied DMRS symbols and data symbols in PSSCH as follows as showedin FIG. 18. In one example, the same pre-coder(s) are applied to DMRSsymbols 2 and 5 (1810 and 1811) and data symbols {0, 1, 3, 4, 6} inPSSCH in one subframe. In one example, the same pre-coder(s) are appliedto DMRS symbols 8 and 11 (1812 and 1813) and data symbols {7, 9, 10, 12}in PSSCH in one subframe.

FIG. 20 illustrates an example PRB configuration 2000 according toembodiments of the present disclosure. The embodiment of the PRBconfiguration 2000 illustrated in FIG. 20 is for illustration only. FIG.20 does not limit the scope of this disclosure to any particularimplementation

In one embodiment, the UE can be configured to assume the samepre-coder(s) are applied to one continuous PRB sets with one or morePRBs in frequency domain. In one example, the UE can be configured toassume the pre-coder(s) on DMRS symbol is changed every PRB. Asillustrated in FIG. 20, the UE can be configured to assume thepre-coder(s) applied to PRB0, PRB1, . . . , PRB9 within the PSSCHallocation are different and the UE cannot use the DMRS signal acrossthe PRBs to estimate the channel.

In one example, the UE can be configured to assume the pre-coder(s) onDMRS symbol is changed every two PRB. As illustrated in FIG. 20, the UEcan be configured to assume the pre-coder(s) applied to each PRB pair{PRB0, PRB1}, {PRB2, PRB3}, {PRB4, PRB5}, {PRB6, PRB7}, {PRB8, PRB9}within the PSSCH allocation are different and the UE can use the DMRSsignal within each of those the PRB pair to estimate the channel.

In one example, the UE can be configured to assume the pre-coder(s) onDMRS symbol is changed every 4 PRBs. As illustrated in FIG. 20, the UEcan be configured to assume the pre-coder(s) applied to {PRB0, PRB1,PRB2, PRB3}, {PRB4, PRB5, PRB6, PRB7}, {PRB8, PRB9} within the PSSCHallocation are different and the UE can use the DMRS signal within eachof those PRB subset/bundling set to estimate the channel.

In one embodiment, the UE can be configured to assume the samepre-coder(s) are applied to each continuous N subcarrier in frequencydomain in one OFDM symbol. The value of N can be 1/2/3/4/6/12/24/48.

In some embodiments, the transmission scheme for PSSCH in V2V/V2X linkcan be: pre-coder cycling across subcarriers and/or OFDM symbols; thecombination of SFBC and pre-coder cycling across subcarriers and/or OFDMsymbols; and/or the combination of STBC and pre-coder cycling acrosssubcarriers and/or OFDM symbols.

In one embodiment, the transmission scheme of pre-coder cycling forPSSCH can be one of the following alternatives: N pre-coders are cycledthrough by transmitter UE in frequency domain (e.g., the pre-coders canbe cycled across PRBs and/or the pre-coders can be cycled across REs); Mpre-coders are cycled through by transmitter UE in time domain (e.g.,the pre-corders can be cycled across every few OFDM symbols and/or thepre-coders can be cycled across every OFDM symbol subset); and/or thecombination of the above two alternatives.

FIG. 21A illustrates an example DMRS configuration and pre-coder set2100 according to embodiments of the present disclosure. The embodimentof the DMRS configuration and pre-coder set 2100 illustrated in FIG. 21Ais for illustration only. FIG. 21A does not limit the scope of thisdisclosure to any particular implementation

In one method, the transmitter UE has two pre-coder sets, pre-coder set1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } and pre-coder set 2 {w_(2,1),w_(2,2), . . . , w_(2,N) ₂ }. The pre-coder set 1 can be applied toPSSCH data OFDM symbols {0, 1, 3, 4, 6} and the pre-coder set 2 canapplied to PSSCH data OFDM symbols {7, 9, 10, 12}, as illustrated inFIG. 21A. In each symbol of PSCCH data OFDM symbols {0, 1, 3, 4, 6}, thepre-coders in pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } canbe cycled in frequency domain and across every 1/2/3/4/6/12/24/48subcarriers.

In each symbol of PSCCH data OFDM symbols {7, 9, 10, 12}, the pre-codersin pre-coder set 2 {w_(2,1), w_(2,2), . . . w_(2,N) ₂ } can be cycled infrequency domain and can be cycled across every 1/2/3/4/6/12/24/48subcarriers.

Different cycling patterns in frequency domain can be applied to OFDMsymbols sets {0, 1, 3, 4, and 6} ad {7, 9, 10, and 12}. In one example,the pre-coder set 1 can be applied to PSSCH OFDM symbol set {0, 1, 3, 4}and the pre-coder set 2 can be applied to PSCCH OFDM symbol set {6, 7,9, 10, 12}. In each symbol in symbol set {0, 1, 3, 4}, the pre-coders inpre-coder set 1 can be cycled across every 48/24/12/6/4/3/2/1subcarriers. In each symbol in symbol set {6, 7, 9, 10, 12}, theprec-coders in pre-coder set 2 can be cycled across every48/24/12/6/4/3/2/1 subcarriers.

The number of pre-coders in pre-coder set 1, N₁, can be 1 or more thanone. The number of pre-coders in pre-coder set 2, N₂, can be 1 or morethan one. The number of pre-coders in pre-coder set 1 and 2 can be equalor different.

FIG. 21B illustrates another example DMRS configuration and pre-coderset 2130 according to embodiments of the present disclosure. Theembodiment of the DMRS configuration and pre-coder set 2130 illustratedin FIG. 21B is for illustration only. FIG. 21B does not limit the scopeof this disclosure to any particular implementation.

In one method, the transmitter UE has four pre-coder sets, pre-coder set1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } pre-coder set 2 {w_(2,1),w_(2,2), . . . , w_(2,N) ₂ }, pre-coder set 3 {w_(3,1), w_(3,2), . . . ,w_(3,N) ₃ }, and pre-coder set 4 {w_(4,1), w_(4,2), . . . , w_(4,N) ₄ },as illustrated in FIG. 21B. The pre-coder set 1 can be applied to PSSCHdata OFDM symbols {0, 1, 3}. The pre-coder set 2 can applied to PSSCHdata OFDM symbols {4, 6}. The pre-coder set 3 can applied to PSSCH dataOFDM symbols {7, 9}. The pre-coder set 4 can applied to PSSCH data OFDMsymbols {10, 12}.

In each symbol of PSCCH data OFDM symbols {0, 1, 3}, the pre-coders inpre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } can be cycled infrequency domain and across every 1/2/3/4/6/12/24/48 subcarriers. Ineach symbol of PSCCH data OFDM symbols {4, 6}, the pre-coders inpre-coder set 2 {w_(2,1), w_(2,2), . . . , w_(2,N) ₂ } can be cycled infrequency domain and across every 1/2/3/4/6/12/24/48 subcarriers. Ineach symbol of PSCCH data OFDM symbols {7, 9}, the pre-coders inpre-coder set 3 {w_(3,1), w_(3,2), . . . , w_(3,N) ₃ } can be cycled infrequency domain and across every 1/2/3/4/6/12/24/48 subcarriers. Ineach symbol of PSCCH data OFDM symbols {10, 12}, the pre-coders inpre-coder set 4 {w_(4,1), w_(4,2), . . . , w_(4,N) ₄ } can be cycled infrequency domain and across every 1/2/3/4/6/12/24/48 subcarriers.

In one example, the pre-coder set 1 can be applied to PSSCH data OFDMsymbols {0, 1}, the pre-coder set 2 can be applied to PSSCH data OFDMsymbols {3, 4}, the pre-coder set 3 can be applied to PSSCH data OFDMsymbols {6, 7}, and the pre-coder set 4 can be applied to PSSCH dataOFDM symbols {9, 10, 12}. The number of pre-coders in pre-coder set 1,N₁, can be 1 or more than one. The number of pre-coders in pre-coder set2, N₂, can be 1 or more than one. The number of pre-coders in pre-coderset 3, N₃, can be 1 or more than one. The number of pre-coders inpre-coder set 4, N₄, can be 1 or more than one. The numbers ofpre-coders in pre-coder sets 1, 2, 3 and 4 can be different or equal.

FIG. 21C illustrates yet another example DMRS configuration andpre-coder set 2150 according to embodiments of the present disclosure.The embodiment of the DMRS configuration and pre-coder set 2150illustrated in FIG. 21C is for illustration only. FIG. 21C does notlimit the scope of this disclosure to any particular implementation.

In one embodiment, the transmitter UE has one pre-coder set, pre-coderset 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } as illustrated in FIG. 21C.The pre-coder set 1 can be applied to all PSSCH data OFDM symbols {0, 1,3, 4, 6, 7, 9, 10, 12} in one subframe. In each symbol of PSCCH dataOFDM symbols {0, 1, 3, 4, 6, 7, 9, 10, 12}, the pre-coders in pre-coderset 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } can be cycled in frequencydomain and across every 1/2/3/4/6/12/24/48 subcarriers. The number ofpre-coders in pre-coder set 1, N₁, can be one or more than one.

In one embodiment, the transmission scheme for PSSCH can be thecombination of SFBC and pre-coder cycling in frequency/time domain. Inone example, the codeword of PSSCH can be first mapped to two layers:

$\begin{matrix}{{x^{(0)}(i)} = {d( {2i} )}} \\{{x^{(1)}(i)} = {d( {{2i} + 1} )}}\end{matrix}$

where d(n) is the modulation symbol(s) in the codeword of PSSCH andx⁽⁰⁾(i) and x⁽¹⁾(i) are the first and second layers, respectively.

Then, in one OFDM symbol of PSSCH data OFDM symbols {0, 1, 3, 4, 6, 7,9, 10, 12}, the two layers are mapped to two antenna ports p₀ and p₁ asfollows:

$\begin{bmatrix}{y^{(p_{0})}( {2i} )} \\{y^{(p_{1})}( {2i} )} \\{y^{(p_{0})}( {{2i} + 1} )} \\{y^{(p_{1})}( {{2i} + 1} )}\end{bmatrix} = {{\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 0 & j & 0 \\0 & {- 1} & 0 & j \\0 & 1 & 0 & j \\1 & 0 & {- j} & 0\end{bmatrix}}\begin{bmatrix}{{Re}( {x^{(0)}(i)} )} \\{{Re}( {x^{(1)}(i)} )} \\{{Im}( {x^{(0)}(i)} )} \\{{Im}( {x^{(1)}(i)} )}\end{bmatrix}}$

where i=0, 1, . . . , M_(sc) ^(PSSCH)/2−1. Then on each of antenna portsof PSSCH, p₀ and p₁, pre-coder cycling can be applied.

The pre-coder cycling for antenna ports p₀ and p₁ can be one of thefollowings. In one example, the transmitter UE has two pre-coder sets,pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } and pre-coder set2 {w_(2,1), w_(2,2), . . . , w_(2,N) ₂ }. The pre-coder set 1 can beapplied to PSSCH data OFDM symbols {0, 1, 3, 4, 6} and the pre-coder set2 can be applied to PSSCH data OFDM symbols {7, 9, 10, 12}. In eachsymbol of PSCCH data OFDM, the pre-coders in corresponding pre-coder setcan be cycled in frequency domain and across every 2/4/6/12/24/48subcarriers.

In another example, the transmitter UE has two pre-coder sets, pre-coderset 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } and pre-coder set 2{w_(2,1), w_(2,2,) . . . , w_(2,N) ₂ }. The pre-coder set 1 can beapplied to PSSCH data OFDM symbols {0, 1, 3, 4} and the pre-coder set 2can be applied to PSSCH data OFDM symbols {6, 7, 9, 10, 12}. In eachsymbol of PSCCH data OFDM symbols, the pre-coders in correspondingpre-coder set can be cycled in frequency domain and across every2/4/6/12/24/48 subcarriers.

In yet another example, the transmitter UE has four pre-coder sets,pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ }, pre-coder set 2{w_(2,1), w_(2,2), . . . , w_(2,N) ₂ }, pre-coder set 3 {w_(3,1),w_(3,2), . . . , w_(3,N) ₃ }, and pre-coder set 4 {w_(4,1), w_(4,2), . .. , w_(4,N) ₄ }. The pre-coder set 1 can be applied to PSSCH data OFDMsymbols {0, 1, 3}. The pre-coder set 2 can applied to PSSCH data OFDMsymbols {4, 6}. The pre-coder set 3 can applied to PSSCH data OFDMsymbols {7, 9}. The pre-coder set 4 can applied to PSSCH data OFDMsymbols {10, 12}. In each symbol of PSCCH data OFDM symbols, thepre-coders in corresponding pre-coder set can be cycled in frequencydomain and across every 2/4/6/12/24/48 subcarriers.

In yet another example, the transmitter UE has four pre-coder sets,pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } pre-coder set 2{w_(2,1), w_(2,2), . . . , w_(2,N) ₂ }, pre-coder set 3 {w_(3,1),w_(3,2), . . . , w_(3,N) ₃ }, and pre-coder set 4 {w_(4,1), w_(4,2), . .. , w_(4,N) ₄ }. The pre-coder set 1 can be applied to PSSCH data OFDMsymbols {0, 1}. The pre-coder set 2 can applied to PSSCH data OFDMsymbols {3, 4}. The pre-coder set 3 can applied to PSSCH data OFDMsymbols {6, 7}. The pre-coder set 4 can applied to PSSCH data OFDMsymbols {9, 10, 12}. In each symbol of PSCCH data OFDM symbols, thepre-coders in corresponding pre-coder set can be cycled in frequencydomain and across every 2/4/6/12/24/48 subcarriers.

In yet another example, the transmitter UE has one pre-coder set,pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ }, as illustratedin FIG. 21C. The pre-coder set 1 can be applied to all PSSCH data OFDMsymbols {0, 1, 3, 4, 6, 7, 9, 10, 12} in one subframe. In each symbol ofPSCCH data OFDM symbols {0, 1, 3, 4, 6, 7, 9, 10, 12}, the pre-coders inpre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } can be cycled infrequency domain and across every 2/4/6/12/24/48 subcarriers.

In yet another example, the transmitter applies pre-coder w_(1,1) onPSSCH transmitted on OFDM symbols {0, 1, 3, 4, 6} and DMRS on symbols{2, 5} of antenna port p₀. The transmitter UE applies pre-coder w_(1,2)on PSSCH transmitted on OFDM symbols {7, 9, 10, 12} and DMRS on symbols{8, 11} of antenna port p₀. The receiver UE can be requested to assumepre-coders w_(1,1) and w_(1,2) are different. The transmitter appliespre-coder w_(2,1) on PSSCH transmitted on OFDM symbols {0, 1, 3, 4, 6}and DMRS on symbols {2, 5} of antenna port p₁. The transmitter UEapplies pre-coder w_(2,2) on PSSCH transmitted on OFDM symbols {7, 9,10, 12} and DMRS on symbols {8, 11} of antenna port p₁. The receiver UEcan be requested to assume pre-coders w_(2,1) and w_(2,2) are different.

In yet another example, the transmitter applies pre-coder w_(1,1) onPSSCH transmitted on OFDM symbols {0, 1, 3, 4, 6} and DMRS on symbols{2, 5} of antenna port p₀. The transmitter UE applies pre-coder w_(1,2)on PSSCH transmitted on OFDM symbols {7, 9, 10, 12} and DMRS on symbols{8, 11} of antenna port p₀. The receiver UE can be requested to assumepre-coders w_(1,1) and w_(1,2) are different. The transmitter appliespre-coder w₂ on PSSCH transmitted on OFDM symbols {0, 1, 3, 4, 6, 7, 9,10, 12} and DMRS on symbols {2, 5, 8, 11} of antenna port p₁.

In yet another example, the transmitter applies pre-coder w₁ on PSSCHtransmitted on OFDM symbols {0, 1, 3, 4, 6, 7, 9, 10, 12} and DMRS onsymbols {2, 5, 8, 11} of antenna port p₀. The transmitter appliespre-coder w_(2,1) on PSSCH transmitted on OFDM symbols {0, 1, 3, 4, 6}and DMRS on symbols {2, 5} of antenna port p₁. The transmitter UEapplies pre-coder w_(2,2) on PSSCH transmitted on OFDM symbols {7, 9,10, 12} and DMRS on symbols {8, 11} of antenna port p₁. The receiver UEcan be requested to assume pre-coders w_(2,1) and w_(2,2) are different.

One of the aforementioned embodiments can be used for antenna port p₀.One of the above methods can be used for antenna port p₁. Different orsame pre-coder cycling method can be applied to the antenna ports p₀ andp₁.

In one embodiment, the transmission scheme for PSSCH can be thecombination of STBC and pre-coder cycling in frequency/time domain. Inone example, the SBTC scheme over two antenna ports can be transmittedon OFDM symbol pairs {0, 1}, {3, 4}, {6, 7} and {9, 10}. One OFDM symbol12, only antenna port p₀ is mapped. An example of transmitting PSSCHcodeword {x(0), x(1), x(2), . . . , x(M_(sc) ^(PSSCH)×9−1)} is shown inTABLE 5A through 5D.

TABLE 5A PSSCH codeword Subcarrier OFDM symbol index index 0 1 2 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(0)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(1)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(1)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(0)}{\sqrt{2}}}\end{matrix}$ DMRS symbol 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(9)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(10)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(10)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(9)}{\sqrt{2}}}\end{matrix}$ 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(18)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(19)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(19)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(18)}{\sqrt{2}}}\end{matrix}$ 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(27)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(28)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(28)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(27)}{\sqrt{2}}}\end{matrix}$ . . . . . . M_(sc) ^(PSSCH) − 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(Z)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 1} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 1} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(Z)}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

TABLE 5B PSSCH codeword Subcarrier OFDM symbol index index 3 4 5 6 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(2)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(3)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(3)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(2)}{\sqrt{2}}}\end{matrix}$ DMRS symbol $\quad\begin{matrix}{y^{p_{0}} = \frac{x(4)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(5)}}{\sqrt{2}}}\end{matrix}$ 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(11)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(12)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(12)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(11)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(13)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(14)}}{\sqrt{2}}}\end{matrix}$ 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(20)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(21)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(21)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(20)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(22)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(23)}}{\sqrt{2}}}\end{matrix}$ 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(29)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(30)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(30)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(29)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(31)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(32)}}{\sqrt{2}}}\end{matrix}$ . . . M_(sc) ^(PSSCH) − 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 2} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 3} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 3} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 2} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 4} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 5} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

TABLE 5C PSSCH codeword Subcarrier OFDM symbol index index 7 8 9 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(5)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(4)}{\sqrt{2}}}\end{matrix}$ DMRS symbol $\quad\begin{matrix}{y^{p_{0}} = \frac{x(6)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(7)}}{\sqrt{2}}}\end{matrix}$ 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(14)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(13)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(15)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(16)}}{\sqrt{2}}}\end{matrix}$ 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(23)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(22)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(24)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(25)}}{\sqrt{2}}}\end{matrix}$ 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(32)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(31)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(33)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(34)}}{\sqrt{2}}}\end{matrix}$ . . . . . . M_(sc) ^(PSSCH) − 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 5} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 4} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 6} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 7} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

TABLE 5D PSSCH codeword Subcarrier OFDM symbol index index 10 11 12 13 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(7)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(6)}{\sqrt{2}}}\end{matrix}$ DMRS symbol y^(p₀) = x(8) 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(16)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(15)}{\sqrt{2}}}\end{matrix}$ y^(p₀) = x(17) 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(25)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(24)}{\sqrt{2}}}\end{matrix}$ y^(p₀) = x(26) 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(34)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(33)}{\sqrt{2}}}\end{matrix}$ y^(p₀) = x(35) . . . M_(sc) ^(PSSCH) − 1$\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 7} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 6} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ y^(p₀) = x(M_(sc)^(PSSCH) × 9 − 1)

Then on each of antenna ports of PSSCH, p₀ and p₁, pre-coder cycling canbe applied. The pre-coder cycling for antenna ports p₀ and p₁ can be oneof the followings.

In one example, the transmitter UE has two pre-coder sets, pre-coder set1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } and pre-coder set 2 {w_(2,1),w_(2,2), . . . , w_(2,N) ₂ }. The pre-coder set 1 can be applied toPSSCH data OFDM symbols {0, 1, 3, 4} and the pre-coder set 2 can beapplied to PSSCH data OFDM symbols {6, 7, 9, 10, 12}. In each symbol ofPSCCH data OFDM symbols, the pre-coders in corresponding pre-coder setcan be cycled in frequency domain and across every 2/4/6/12/24/48subcarriers.

In another example, the transmitter UE has four pre-coder sets,pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } pre-coder set 2{w_(2,1), w_(2,2), . . . , w_(2,N) ₂ }, pre-coder set 3 {w_(3,1),w_(3,2), . . . , w_(3,N) ³}, and pre-coder set 4 {w_(4,1), w_(4,2), . .. , w_(4,N) ₄ }. The pre-coder set 1 can be applied to PSSCH data OFDMsymbols {0, 1}. The pre-coder set 2 can applied to PSSCH data OFDMsymbols {3, 4}. The pre-coder set 3 can applied to PSSCH data OFDMsymbols {6, 7}. The pre-coder set 4 can applied to PSSCH data OFDMsymbols {9, 10, 12}. In each symbol of PSCCH data OFDM symbols, thepre-coders in corresponding pre-coder set can be cycled in frequencydomain and across every 1/2/3/4/6/12/24/48 subcarriers.

In yet another example, the transmitter UE has one pre-coder set,pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } as illustrated inFIG. 21C. The pre-coder set 1 can be applied to all PSSCH data OFDMsymbols {0, 1, 3, 4, 6, 7, 9, 10, 12} in one subframe. In each symbol ofPSCCH data OFDM symbols {0, 1, 3, 4, 6, 7, 9, 10, 12}, the pre-coders inpre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } can be cycled infrequency domain and across every 1/2/3/4/6/12/24/48 subcarriers.

In yet another example, the transmitter applies pre-coder w_(1,1) onPSSCH transmitted on OFDM symbols {0, 1, 3, 4} and DMRS on symbols {2,5} of antenna port p₀. The transmitter UE applies pre-coder w_(1,2) onPSSCH transmitted on OFDM symbols {6, 7, 9, 10, 12} and DMRS on symbols{8, 11} of antenna port p₀. The receiver UE can be requested to assumepre-coders w_(1,1) and w_(1,2) are different. The transmitter appliespre-coder w_(2,1) on PSSCH transmitted on OFDM symbols {0, 1, 3, 4} andDMRS on symbols {2, 5} of antenna port p₁. The transmitter UE appliespre-coder w_(3,2) on PSSCH transmitted on OFDM symbols {6, 7, 9, 10} andDMRS on symbols {8, 11} of antenna port p₁. The receiver UE can berequested to assume pre-coders w_(2,1) and w_(2,2) are different.

In yet another example, the transmitter applies pre-coder w_(1,1) onPSSCH transmitted on OFDM symbols {0, 1, 3, 4} and DMRS on symbols {2,5} of antenna port p₀. The transmitter UE applies pre-coder w_(1,2) onPSSCH transmitted on OFDM symbols {6, 7, 9, 10, 12} and DMRS on symbols{8, 11} of antenna port p₀. The receiver UE can be requested to assumepre-coders w_(1,1) and w_(1,2) are different. The transmitter appliespre-coder w₂ on PSSCH transmitted on OFDM symbols {0, 1, 3, 4, 6, 7, 9,10} and DMRS on symbols {2, 5, 8, 11} of antenna port p₁.

In yet another example, the transmitter applies pre-coder w₁ on PSSCHtransmitted on OFDM symbols {0, 1, 3, 4, 6, 7, 9, 10, 12} and DMRS onsymbols {2, 5, 8, 11} of antenna port p₀. The receiver UE can berequested to assume pre-coders w_(1,1) and w_(1,2) are different. Thetransmitter applies pre-coder w_(2,1) on PSSCH transmitted on OFDMsymbols {0, 1, 3, 4} and DMRS on symbols {2, 5} of antenna port p₁. Thetransmitter UE applies pre-coder w_(3,2) on PSSCH transmitted on OFDMsymbols {6, 7, 9, 10} and DMRS on symbols {8, 11} of antenna port p₁.The receiver UE can be requested to assume pre-coders w_(2,1) andw_(2,2) are different.

One of the aforementioned embodiments can be used for antenna port p₀.One of the above methods can be used for antenna port p₁. Different orsame pre-coder cycling method can be applied to the antenna ports p₀ andp₁.

In one embodiment, the SBTC scheme over two antenna ports can betransmitted on OFDM symbol pairs {1, 3}, {4, 6}, {7, 9} and {10, 12}.One OFDM symbol 0, only antenna port p₀ is mapped. An example oftransmitting PSSCH codeword {x(0), x(1), x(2), . . . , x(M_(sc)^(PSSCH)×9−1)} is shown in TABLE 5E through 5H.

TABLE 5E PSSCH codeword Subcarrier OFDM symbol index index 0 1 2 0y^(p₀) = x(0) $\quad\begin{matrix}{y^{p_{0}} = \frac{x(1)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(2)}}{\sqrt{2}}}\end{matrix}$ DMRS symbol 1 y^(p₀) = x(9) $\quad\begin{matrix}{y^{p_{0}} = \frac{x(10)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(11)}}{\sqrt{2}}}\end{matrix}$ 2 y^(p₀) = x(18) $\quad\begin{matrix}{y^{p_{0}} = \frac{x(19)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(20)}}{\sqrt{2}}}\end{matrix}$ 3 y^(p₀) = x(27) $\quad\begin{matrix}{y^{p_{0}} = \frac{x(28)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(29)}}{\sqrt{2}}}\end{matrix}$ . . . M_(sc) ^(PSSCH) − 1y^(p₀) = x((M_(sc)^(PSSCH) − 1) × 9) $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 1} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 2} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

TABLE 5F PSSCH codeword Subcarrier OFDM symbol index index 3 4 5 6 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(2)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(1)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(3)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(4)}}{\sqrt{2}}}\end{matrix}$ DMRS symbol $\quad\begin{matrix}{y^{p_{0}} = \frac{x(4)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(3)}{\sqrt{2}}}\end{matrix}$ 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(11)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(10)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(12)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(13)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(13)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(12)}{\sqrt{2}}}\end{matrix}$ 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(20)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(19)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(21)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(22)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(22)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(21)}{\sqrt{2}}}\end{matrix}$ 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(29)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(28)}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(30)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(31)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(31)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(30)}{\sqrt{2}}}\end{matrix}$ . . . M_(sc) ^(PSSCH) − 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 2} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 1} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 3} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 4} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 4} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 3} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

TABLE 5G PSSCH codeword Subcarrier OFDM symbol index index 7 8 9 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(5)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(6)}}{\sqrt{2}}}\end{matrix}$ DMRS symbol $\quad\begin{matrix}{y^{p_{0}} = \frac{x(6)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(5)}{\sqrt{2}}}\end{matrix}$ 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(14)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(15)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(15)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(14)}{\sqrt{2}}}\end{matrix}$ 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(23)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(24)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(24)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(23)}{\sqrt{2}}}\end{matrix}$ 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(32)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(33)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(33)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(32)}{\sqrt{2}}}\end{matrix}$ . . . M_(sc) ^(PSSCH) − 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 5} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 6} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 6} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 5} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

TABLE 5H PSSCH codeword Subcarrier OFDM symbol index index 10 11 12 13 0$\quad\begin{matrix}{y^{p_{0}} = \frac{x(7)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(8)}}{\sqrt{2}}}\end{matrix}$ DMRS symbol $\quad\begin{matrix}{y^{p_{0}} = \frac{x(8)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(7)}{\sqrt{2}}}\end{matrix}$ 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(16)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(17)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(17)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(16)}{\sqrt{2}}}\end{matrix}$ 2 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(25)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(26)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(26)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(25)}{\sqrt{2}}}\end{matrix}$ 3 $\quad\begin{matrix}{y^{p_{0}} = \frac{x(34)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}(35)}}{\sqrt{2}}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x(35)}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}(34)}{\sqrt{2}}}\end{matrix}$ . . . M_(sc) ^(PSSCH) − 1 $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 7} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{- {x^{*}( {Z + 8} )}}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$ $\quad\begin{matrix}{y^{p_{0}} = \frac{x( {Z + 8} )}{\sqrt{2}}} \\{y^{p_{1}} = \frac{x^{*}( {Z + 7} )}{\sqrt{2}}} \\{Z = {( {M_{sc}^{PSSCH} - 1} ) \times 9}}\end{matrix}$

Then on each of antenna ports of PSSCH, p₀ and p₁, pre-coder cycling canbe applied. The pre-coder cycling for antenna ports p₀ and p₁ can be oneof the followings. In one example, the transmitter UE has two pre-codersets, pre-coder set 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } andpre-coder set 2 {w_(2,1), w_(2,2), . . . , w_(2,N) ₂ }. The pre-coderset 1 can be applied to PSSCH data OFDM symbols {0, 1, 3, 4, 6} and thepre-coder set 2 can be applied to PSSCH data OFDM symbols {7, 9, 10,12}. In each symbol of PSCCH data OFDM, the pre-coders in correspondingpre-coder set can be cycled in frequency domain and across every1/2/3/4/6/12/24/48 subcarriers.

In one example, the transmitter UE has four pre-coder sets, pre-coderset 1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } pre-coder set 2 {w_(2,1),w_(2,2), . . . , w_(2,N) ₂ }, pre-coder set 3 {w_(3,1), w_(3,2), . . . ,w_(3,N) ₃ }, and pre-coder set 4 {w_(4,1), w_(4,2), . . . , w_(4,N) ₄ }.The pre-coder set 1 can be applied to PSSCH data OFDM symbols {0, 1, 3}.The pre-coder set 2 can applied to PSSCH data OFDM symbols {4, 6}. Thepre-coder set 3 can applied to PSSCH data OFDM symbols {7, 9}. Thepre-coder set 4 can applied to PSSCH data OFDM symbols {10, 12}. In eachsymbol of PSCCH data OFDM symbols, the pre-coders in correspondingpre-coder set can be cycled in frequency domain and across every1/2/3/4/6/12/24/48 subcarriers.

In one example, the transmitter UE has one pre-coder set, pre-coder set1 {w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } as illustrated in FIG. 21C. Thepre-coder set 1 can be applied to all PSSCH data OFDM symbols {0, 1, 3,4, 6, 7, 9, 10, 12} in one subframe. In each symbol of PSCCH data OFDMsymbols {0, 1, 3, 4, 6, 7, 9, 10, 12}, the pre-coders in pre-coder set 1{w_(1,1), w_(1,2), . . . , w_(1,N) ₁ } can be cycled in frequency domainand across every 1/2/3/4/6/12/24/48 subcarriers.

In one example, the transmitter applies pre-coder w_(1,1) on PSSCHtransmitted on OFDM symbols {0, 1, 3, 4, 6} and DMRS on symbols {2, 5}of antenna port p₀. The transmitter UE applies pre-coder w_(1,2) onPSSCH transmitted on OFDM symbols {7, 9, 10, 12} and DMRS on symbols {8,11} of antenna port p₀. The receiver UE can be requested to assumepre-coders w_(1,1) and w_(1,2) are different. The transmitter appliespre-coder w_(2,1) on PSSCH transmitted on OFDM symbols {1, 3, 4, 6} andDMRS on symbols {2, 5} of antenna port p₁. The transmitter UE appliespre-coder w_(3,2) on PSSCH transmitted on OFDM symbols {7, 9, 10, 12}and DMRS on symbols {8, 11} of antenna port p₁. The receiver UE can berequested to assume pre-coders w_(2,1) and w_(2,2) are different.

In one example, the transmitter applies pre-coder w_(1,1) on PSSCHtransmitted on OFDM symbols {0, 1, 3, 4, 6} and DMRS on symbols {2, 5}of antenna port p₀. The transmitter UE applies pre-coder w_(1,2) onPSSCH transmitted on OFDM symbols {7, 9, 10, 12} and DMRS on symbols {8,11} of antenna port p₀. The receiver UE can be requested to assumepre-coders w_(1,1) and w_(1,2) are different. The transmitter appliespre-coder w₂ on PSSCH transmitted on OFDM symbols {1, 3, 4, 6, 7, 9, 10,12} and DMRS on symbols {2, 5, 8, 11} of antenna port p₁.

In one example, the transmitter applies pre-coder w₁ on PSSCHtransmitted on OFDM symbols {0, 1, 3, 4, 6, 7, 9, 10, 12} and DMRS onsymbols {2, 5, 8, 11} of antenna port p₀. The transmitter appliespre-coder w_(2,1) on PSSCH transmitted on OFDM symbols {1, 3, 4, 6} andDMRS on symbols {2, 5} of antenna port p₁. The transmitter UE appliespre-coder w_(3,2) on PSSCH transmitted on OFDM symbols {7, 9, 10, 12}and DMRS on symbols {8, 11} of antenna port p₁. The receiver UE can berequested to assume pre-coders w_(2,1) and w_(2,2) are different.

One of the aforementioned embodiments can be used for antenna port p₀.One of the above methods can be used for antenna port p₁. Different orsame pre-coder cycling method can be applied to the antenna ports p₀ andp₁.

If transmit diversity scheme is applied to PSSCH, the correspondingcontrol information sent in PSCCH may indicate the related informationto a UE so that the UE can decode the PSSCH correctly. The controlinformation can indicate one or more of the following information:whether non-transmit diversity (i.e., single port transmission definedin LTE specification) or transmission diversity scheme is used in theindicated PSSCH allocation; and which transmit diversity scheme is usedin the indicated PSSCH allocation.

In one embodiment, N bits in the reserved information bits of SCI format1 can be used to indicate the information of transmit diversity. Theadvantage of that embodiment is that a UE can still decode the SCIformat 1 sent for PSSCH with transmit diversity and obtain theallocation information of PSSCH.

In one example, 1 bit b₀ in the reserved information bits of SCI format1 can be used to indicate the information of transmit diversity incorresponding PSSCH. The value of 1 bit can indicate whethernon-transmit diversity transmission (i.e., single port transmissiondefined in LTE specification) or transmit diversity scheme is used inthe indicated PSSCH as shown in TABLE 6A.

TABLE 6A Bit value b₀ Bit value Usage 0 single port transmission schemedefined in LTE specification in used in the indicated PSSCH 1 Transmitdiversity scheme is used in the indicated PSSCH

The transmit diversity can be predefined in the specification orconfigured through system information or high layer signaling (e.g.,RRC). The transmit diversity indicated b₀=1 can be one of thefollowings: SFBC; STBC; slot-level pre-coder cycling; sub-slot levelpre-coder cycling; combination of slot-level pre-coder cycling and SFBCor STBC; and/or Combination of sub-slot level pre-coder cycling and SFBCor STBC.

In one example, 2 bit b₀b₁ in the reserved information bits of SCIformat 1 can be used to indicate the information of transmit diversityin corresponding PSSCH. The value of 2 bit can indicate whethernon-transmit diversity transmission (i.e., single port transmissiondefined in LTE specification) or transmit diversity scheme is used inthe indicated PSSCH, and also which transmit diversity scheme is used inthe indicated PSSCH as shown in TABLE 6B.

TABLE 6B Bit values b₀b₁ Bit value Usage 00 single port transmissionscheme defined in LTE specification is used in the indicated PSSCH 01Transmit diversity scheme 1 is used in the indicated PSSCH 10 Transmitdiversity scheme 2 is used in the indicated PSSCH 11 Transmit diversityscheme 3 is used in the indicated PSSCH

The transmit diversity schemes 1/2/3 can be predefined in thespecification or configured through system information or high layersignaling (e.g., RRC). Each of the transmit diversity schemeconfiguration can include one or more of the following information: thetransmission scheme for PSSCH; and/or the mapping of DMRS.

In one example, b₀b₁=01 can indicate that slot-level pre-coder cyclingor sub-slot level pre-coder cycling is applied to the indicated PSSCHand DMRS has one antenna port. b₀b₁=10 can indicate that SFBC scheme (orSTBC) is applied to the indicated PSSCH and the DMRS has two antennaports. b₀b₁=11 can indicate that slot-level pre-coder cycling and SFBCscheme is applied to the indicated PSSCH and the DMRS has two antennaports, and the UE can be indicated that different pre-coders are appliedon the first slot and second slot for each DMRS antenna port. b₀b₁=11can indicate that slot-level pre-coder cycling and SFBC scheme (or STBC)is applied to the indicated PSSCH and the DMRS has two antenna ports.

In one example, 3 bit b₀b₁b₂ in the reserved information bits of SCIformat 1 can be used to indicate the information of transmit diversityin corresponding PSSCH. The value of 3 bit can indicate whethernon-transmit diversity transmission (i.e., single port transmissiondefined in LTE specification) or transmit diversity scheme is used inthe indicated PSSCH, and also which transmit diversity scheme is used inthe indicated PSSCH. An example is illustrated in TABLE 6C.

TABLE 6C Bit values b₀b₁ Bit value Usage 000 single port transmissionscheme defined in LTE specification is used in the indicated PSSCH 001Transmit diversity scheme 1 is used in the indicated PSSCH 010 Transmitdiversity scheme 2 is used in the indicated PSSCH 011 Transmit diversityscheme 3 is used in the indicated PSSCH . . . 111 Transmit diversityscheme 7 is used in the indicated PSSCH

The transmit diversity schemes 1˜7 can be predefined in thespecification or configured through system information or high layersignaling (e.g., RRC).

A UE can determine the transmit diversity scheme used for a PSSCHtransmission based on the configuration from system information or highlayer signaling (e.g., RRC) or preconfigured. A UE can be requested touse one transmit diversity scheme for a PSSCH transmission asdynamically indicated by the eNB.

DCI format 5A is used to schedule PSCCH for V2V/V2X. DCI format 5A canbe used to schedule PSCCH that indicates a PSSCH with transmit diversitytransmission scheme.

In one embodiment, DCI format 5A can be scrambled with SL-V-TX-RNTI toindicate the scheduling of PSCCH. The scheduled PSCCH contains SCIformat 1 fields used for the scheduling of PSSCH using transmitdiversity scheme. A UE is requested to use SL-V-TX-RNTI to decode oneDCI format 5A and then can transmit PSSCH as configured by the SCIformat 1 fields in the decoded DCI format 5A. In one example, when theDCI format 5A is scrambled with SL-V-TX-RNTI, one filed can be presentin DCI format 5A to indicate the transmit diversity scheme for PSSCH:transmit diversity scheme—N bits. N can be 1, 2, or 3.

In one example, when the DCI format 5A is scrambled with SL-V-TX-RNTI,the same fields in DCI format A scrambled by SL-V-RNTI are present.Scrambling with SL-V-TX-RNTI can indicate that the scheduled PSSCH canuse transmit diversity scheme, where the transmit diversity scheme canbe configured through system information, RRC signaling orpreconfigured.

In one embodiment, DCI format 5A scrambled with SL-SPS-V-TX-RNTI can beused by eNB to schedule SPS transmission with transmit diversity. In oneexample, when the DCI format 5A is scrambled with SL-SPS-V-TX-RNTI, samefields in DCI format A scrambled by SL-SPS-V-RNTI are present.Scrambling with SL-SPS-V-TX-RNTI can indicate the PSSCH in the scheduledSPS transmission can use transmit diversity scheme, where the transmitdiversity scheme can be configured through system information, RRCsignaling or preconfigured. In one example, when the DCI format 5A isscrambled with SL-SPS-V-TX-RNTI, one field can be present in DCI format5A to indicate the transmit diversity scheme for PSSCH: transmitdiversity scheme—N bits. N can be 1, 2, or 3.

TABLES 6A, 6B, and 6C can be used here for the N bits in DCI format 5Ato indicate the transmit diversity scheme. The V2X UE can be configuredto use the transmit diversity indicated in the DCI format 5A to transmitthe corresponding PSSCH and can also fill the corresponding fields inSCI format 1.

In one embodiment, a mode-3 UE can be configured with the transmissionscheme for PSSCH by the NW semi-statically. In one method, the NW cansignal one transmission scheme to a mode-3 UE. The NW schedules thePSSCH transmission and SCI format content through DCI format 5A. Thenthe UE may fill be transmit diversity scheme field in SCI formattransmitted in the scheduled PSSCH according to the NW configuration andalso choose the transmit scheme for PSSCH according.

In one embodiment, a mode-3 UE can choose the transmission scheme forPSSCH autonomously. In one method, the NW schedules PSCCH and also theSCI format 1 content through a DCI format 5A. The UE can be requested todetermine the transmission scheme for scheduled PSSCH and then fill theSCI format 1 accordingly.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

None of the description in this application should be read as implyingthat any particular element, step, or function is an essential elementthat must be included in the claims scope. The scope of patented subjectmatter is defined only by the claims. Moreover, none of the claims areintended to invoke 35 U.S.C. § 112(f) unless the exact words “means for”are followed by a participle.

What is claimed is:
 1. A user equipment (UE) for a beam failure recoveryin a wireless communication system, the UE comprising: a transceiverconfigured to receive, from a base station (BS), at least one beamfailure detection reference signal (RS) and at least one new candidatebeam RS over a downlink channel; and a processor operably connected tothe transceiver, the processor configured to: identify a set of RSresources including an index for the at least one beam failure detectionRS; identify a set of RS resources including an index for the at leastone new candidate beam RS; and identify a dedicated control-resource set(CORESET) received from the BS for a beam failure recovery request,wherein the transceiver is further configured to: transmit, to the BS,the beam failure recovery request associated with a quality measurementof the at least one beam failure detection RS over a physical randomaccess channel (PRACH); and receive, from the BS, a beam failureresponse in response to the beam failure recovery request based on thededicated CORESET indicated to the UE.
 2. The UE of claim 1, wherein theprocessor is further configured to identify a set of RS resourcesincluding an index corresponding to the at least one beam failuredetection RS that comprises at least one of a periodic channel stateinformation-RS (CSI-RS) or a new radio synchronization signal (NR-SS)block.
 3. The UE of claim 1, wherein the processor is further configuredto identify a set of RS resources including an index corresponding tothe at least one new candidate beam RS that comprises at least one of aperiodic CSI-RS or a synchronization signal/physical broadcastingchannel (SS/PBCH) block.
 4. The UE of claim 1, wherein a physicaldedicated control channel (PDCCH) is transmitted in the dedicatedCORESET to the UE using at least one of a beam pair link (BPL) orspatial quasi co-locate (QCL) assumption information with a reference toat least one RS resource from a set of new candidate beam RS resources.5. The UE of claim 1, wherein the processor is further configured toselect at least one PRACH resource according to one RS resource from aset of new candidate beam RS resources that has L1-RSRP measurement notsmaller than a configured threshold.
 6. The UE of claim 1, wherein thetransceiver is further configured to receive at least one of downlinkcontrol information (DCI) that is scrambled by a cell-radio networktemporary identifier (C-RNTI) as the beam failure response received fromthe BS.
 7. The UE of claim 1, wherein the transceiver is furtherconfigured to receive at least one threshold for a layer 1-referencesignal received power (L1-RSRP) measurement of a new candidate beam RSto the UE and identify at least one RS resource from a set of newcandidate beam RS resources that has L1-RSRP measurement no smaller thanthe at least one threshold.
 8. A base station (BS) for a beam failurerecovery in a wireless communication system, the BS comprising: aprocessor configured to: identify a set of reference signal (RS)resources including an index for at least one beam failure detection RS;and identify a set of RS resources including an index for at least onenew candidate beam RS; and a transceiver operably connected to theprocessor, the transceiver configured to: transmit, to a user equipment(UE), the at least one beam failure detection RS and the at least onenew candidate beam RS over a downlink channel; receive, from the UE, abeam failure recovery request associated with a quality measurement ofthe at least one beam failure detection RS over a physical random accesschannel (PRACH), wherein the processor is further configured to identifya dedicated control-resource set (CORESET) for the beam failure recoveryrequest; and transmit, to the UE, a beam failure response in response tothe beam failure recovery request based on the dedicated CORESETindicated to the UE.
 9. The BS of claim 8, wherein the processor isfurther configured to identify a set of RS resources including an indexcorresponding to the at least one beam failure detection RS thatcomprises at least one of a periodic channel state information-RS(CSI-RS) or a new radio synchronization signal (NR-SS) block.
 10. The BSof claim 8, wherein the processor is further configured to identify aset of RS resources including an index corresponding to the at least onenew candidate beam RS that comprises at least one of a periodic CSI-RSor a synchronization signal/physical broadcasting channel (SS/PBCH)block.
 11. The BS of claim 8, wherein a physical dedicated controlchannel (PDCCH) is transmitted in the dedicated CORESET to the UE usingat least one of a beam pair link (BPL) or spatial quasi co-locate (QCL)assumption information with a reference to one RS resource from a set ofnew candidate beam RS resources.
 12. The BS of claim 8, wherein theindex included in the set of RS resources corresponds to at least one ofa BPL or QCL assumption information.
 13. The BS of claim 8, wherein thetransceiver is further configured to transmit at least one of downlinkcontrol information (DCI) that is scrambled by a cell-radio networktemporary identifier (C-RNTI) as the beam failure response transmittedto the UE.
 14. The BS of claim 8, wherein the transceiver is furtherconfigured to transmit at least one threshold for a layer 1-referencesignal received power (L1-RSRP) measurement of the new candidate newbeam RS to the UE.
 15. A method of a user equipment (UE) for a beamfailure recovery in a wireless communication system, the methodcomprising: receiving, from a base station (BS), at least one beamfailure detection reference signal (RS) and at least one new candidatebeam RS over a downlink channel; identifying a set of RS resourcesincluding an index for the at least one beam failure detection RS;identifying a set of RS resources including an index for the at leastone new candidate beam RS; identifying a dedicated control-resource set(CORESET) received from the BS for a beam failure recovery request;transmitting, to the BS, the beam failure recovery request associatedwith a quality measurement of the at least one beam failure detection RSover a physical random access channel (PRACH); and receiving, from theBS, a beam failure response in response to the beam failure recoveryrequest based on the dedicated CORESET indicated to the UE.
 16. Themethod of claim 15, further comprising identifying a set of RS resourcesincluding an index corresponding to the at least one beam failuredetection RS that comprises at least one of a periodic channel stateinformation-RS (CSI-RS) or a new radio synchronization signal (NR-SS)block.
 17. The method of claim 15, further comprising identifying a setof RS resources including an index corresponding to the at least one newcandidate beam RS that comprises at least one of a periodic CSI-RS or asynchronization signal/physical broadcasting channel (SS/PBCH) block.18. The method of claim 15, wherein a physical dedicated control channel(PDCCH) is transmitted in the dedicated CORESET to the UE using at leastone of a beam pair link (BPL) or spatial quasi co-locate (QCL)assumption information with a reference to at least one RS resource froma set of new candidate beam RS resources.
 19. The method of claim 15,further comprising selecting at least one PRACH resource according toone RS resource from a set of new candidate beam RS resources that hasL1-RSRP measurement not smaller than a configured threshold.
 20. Themethod of claim 15, further comprising: receiving at least one ofdownlink control information (DCI) that is scrambled by a cell-radionetwork temporary identifier (C-RNTI) as the beam failure responsereceived from the BS; receiving at least one threshold for a layer1-reference signal received power (L1-RSRP) measurement of the newcandidate beam RS to the UE; and identifying at least one RS resourcefrom a set of new candidate beam RS resources that has L1-RSRPmeasurement no smaller than the at least one threshold.